How to Optimize Images for Better Search Engine Rankings

by Derek Halpern · 56 comments

WordPress SEO

You may not realize this, but images can generate a TON of traffic from image-based search engines (Google Images for example).

If you want more of this traffic, you must learn how to optimize your images to score some of this traffic.

Luckily, it’s easier than you think… once you know what to do.

And that’s why we’re adding this tutorial to our WordPress SEO for everybody series. So, keep reading.

Image Optimization Best-Practice #1: Alt Text

When you see a picture of a baby crying, you instantly recognize what’s going on in the picture.

The problem is, this instant recognition isn’t possible for search engine spiders at this time. Instead, you must help the spiders understand each of your images with alt text.

What is image alt text?

The short answer is, it’s the text that the search engine uses to understand images.

To include it, you simply add alt="this is your alt text" to your image tag. Here’s an example:

<img src="baby-crying.jpg" alt="Baby Crying" />

It’s that simple.

Image Optimization Best-Practice #2: File Size

You know page load times matter for SEO, right now, right?


So, to ensure that your images don’t torpedo your fast load times, make the image file size as small as possible (without sacrificing quality, of course).

With free tools like Picnik and Image Optimizer at your disposal, there’s no excuse 🙂

Oh, and one more thing…

DO NOT let your browser resize a large image to look smaller.

When you have a large image, and input height and width tags on that image to make the image smaller, people load the large image first, and then the browser resizes it.

To solve it, always use an image editing program to make your image a desired size, and upload that.

Image Optimization Best-Practice #3: File Name

Before you upload your image, pick a descriptive filename—preferably a file name you want that image to rank for—because it will help with your search engine rankings.

For example, if you want to see this in action, just do a sample search and view the images that rank. They almost always have the keyword you searched for in their file name.

Or, see the image below… here with WordPress SEO.

WordPRess SEO Example Search Results

Image Optimization Best-Practice #4: Captions

As of right now, there’s no direct relation between image captions and search engine rankings (that I know of).

However, bounce rates are taken into account.

What do I mean by bounce rate?

If someone searches for a term, clicks on your page, and bounces back to the search page quickly, search engines use that as a factor for rankings.

It makes sense too… Why would someone go back to the search results?

Because the content they clicked on didn’t satisfy what they were looking for.

And that’s where image captions come in.

Next to your headline, image captions are important because they are one of the most well-read pieces of content on your entire site.

So, if you fail to use them, you’re losing out on one more chance to lower your bounce rate.

The Bottom Line

If you spend hours crafting the perfect post, don’t miss out on the chance to optimize your images for maximum search engine benefit. All of these steps should take you no longer than a few minutes, and sometimes, it really can be the “icing on the cake.”

About the Author: Derek Halpern ran marketing at DIYthemes, and is the founder of Social Triggers. To get more tips on how to be confident, sign up to his list here.

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I am aware of Bounce rate being considered by ranking algorithms, especially after Panda update, but this is something new I have learned to use Captions to decrease the bounce rate.
Like the way you write articles Derek, simple and readable with lots of spacing!!

Derek Halpern

Ha ha, Chris used to rip on me for that. I try to keep all paragraphs short, because they’re easier to read that way 😀

Adarsh Thampy

Who told bounce rate is considered for Google rankings?

Danny Cruz

Good one Derek, I wasn’t actually aware of bounce rate affecting your rankings. But it makes perfect sense. -Danny

Jim Stalker

Hey Derek,

Love the stuff you are doing – it helps.

But when is the new version of Thesis coming out?

There there have been so many other themes that have come that have much more baked into them…

Derek Halpern

Not really. The current themes all have similar features, and yet, not one supports the robust category page SEO options that Thesis has… yet.

Thesis 2.0 is being worked on, and we’re looking at launching it as soon as possible.

Richard E

I know picture captions are a good idea.

My question is, if you are using the Post Image as the lead image in Thesis, so it displays correctly at the top of your post and as a thumbnail, how do you get it to display a caption?

And I don’t mean simply alt text (which should be an image description, not a caption) which is what Wordpress often calls a caption, or mouseover text (which only some people can see) – I mean a user-defined caption line run underneath the image – one that doesn’t appear as part of your auto feed to Twitter, or whatever, just under the picture when it appears in the Post.

This does not seem possible. If it is, how’s it done? I’ve been searching for a while with no joy.

And shouldn’t we be using Featured Image for the Post and Thumbnail image at this point and going forward? If so, how?

Thanks! Keep up the good work!

warner blake

My question too … even adding an img title would be better good first step toward captions.

Julie Gomoll

What about the description? I’ve never been clear on where/how that comes into play, or if it does at all.

Tanya at Ignite Your

Thanks so much for this great advice. I have to admit, as good as I have been a optimizing the rest of my site, I have completely overlooked my images. Well no more!

Jeff Sebring

More good advice Derek. I’m curious if anyone has seen results from adding metadata to images or video files.

If you right-click an image and open the properties, with most formats you can add a bunch of information to an image.

This is another one of those things that is very hard or impossible to test, but could very well be used to determine the content of an image. I try to do things that Just Make Sense, even if it isn’t proven to be a factor.


You sir . . . are my hero!

That is exactly what I’ve been searching for—to help with my drawings. Hm . . maybe the other authors should have used your tips ; )

Do you think the text in the image *title* make a difference?

Appreciated, as always,


Joanie McMahon

Awesome article. Thanks guys. I just love thesis!

Willy Christopher

Thanks for the great insight, Derek. I don’t get high volumes of traffic yet ( which is a work in progress), but I started noticing traffic coming from keywords related to my picture captions or tags.

When I GIS for the keywords, my related blog pictures were showing in the top 10 images.

So, the question regarding Bounce rate is this: Are you suggesting that people will stay on the page longer when you have relevant pictures?

Or, do you mean that they are more likely to visit what they feel is relevant because you’ve tagged to pictures properly? So you get better targeted traffic with fewer unique visits, but they are more likely to stay on your site longer (improving bounce rate)?

Again, great article!

Scott Ellis

Derek –

Glad to see you sharing this. I’ve been preaching the importance of paying attention to your images in this regard for years, especially descriptive, acurate image names.

Of note: a good naming convention is to use hyphens “-” between words since they are considered “whitespace” characters whereas underscores “_” are not.

So someone might search for “Derek Halpern” but not likely to search for “Derek_Halpern.”

Now if something in that regard has changed I’d like to know but it’s continued to be my practice.

Dr Senthil Kumar

It is quiet interesting, but my question is, the traffic thro the image search will only copy our images, is it not? Will it help us to improve our Sales or earnings?

Jay Tanna

Perhaps not unless you have products that is of interest to the guy you have just managed to tempt to your site. It is like most advertisements. Most of the time we simply view them and laugh it out but these guys operate in % rate of conversion of viewers of their ads. If they can get 3% then I am sure they are happy and next time they will aim to get 4% and so on.


Re image caption. As far as I can see, the thesis image handling system does not allow a caption to be inserted in an image. Using the media library with html in the body of the blog does. But using the add image and thumbnail in the thesis theme does not.
Why is this. Or am I missing something?

Chris Pearson

Peter, Thesis 1.8.1 allows you to add alt text to both post images and thumbnails.

In the next version, you’ll be able to add captions as well, and you’ll also enjoy tighter integration with the WordPress media library.


I am confused about optimizing. When I upload a picture to image optimizer, there is a limited to file size. How do you optimize in Picnik? This only allow you to resize the file. For example if you like to put 500 by 300 pictures on your site. Flickr allows you to make that file smaller by height and width tags. However, I read that you can keep the same size but still make the file size smaller.

Derek Halpern

When you look at Save and Share, picnik has file quality recommendations, which preserve quality and file size. For example, they specifically say “a sweetspot of really good quality and file size.”

Dan Rippon

Well, talk about perfect timing… I had a client pose a question the other day based on the use of images that I wasn’t able to answer straight off. (And this maybe touches on some of what Richard E mentions above?)

The question came about from discussing Yoast’s Wordpress SEO plugin – and that it appeared unable to “read” information on images the client had previously optimised and inserted via the post image function (compared to those inserted directly to the post). Consequently he wondered if this meant the search engine agents may also have the same issue? Anyone have any thoughts? Is it more likely a limitation of Thesis, or of the plugin?

Pcwizode Web Design

Hi there,

Just wanted to confirm I have found above steps to work when it comes to images, have not always added captions though, but must say looks better and believe it will improve time stayed and over all looks.


* The actual quality of traffic you get from image search is beyond poor. People looking for images are there simply to steal them for their own use. Spending too much time on optimising anything but the filesize is a waste. Do something more productive like, I dunno, anything…cook, clean or do something…

* Bounce rate is NOT the percentage of users who land on your page and ‘bounce’ straight back to the search engine – it is the percentage of users who landed on your page and did not surf to another page on your site.

This can be a bad thing if they’re instantly leaving your site because it’s crap – but it can also mean you have exceptional content that gives the user exactly what they were looking for, alleviating the need to look any further. Therefore, Search Engines don’t use it to rank AT ALL.

If you’re a price comparison site, high bounce rate means you’re crap. If you’re an informational blog, it could mean you’re effing amazing.

Wikipedia must have a bounce rate of about 99.9% – do their rankings slip?

Bounce rate has nothing to do with rankings whatsoever – it is simply a metric for webmasters to gauge the user’s perception of their site.

Next you’ll be telling us to optimize our meta keywords tags, bold huge swathes of text, link out to google (because it’s who you link to) and really think (thought or understand) about our SEO text (search engine optimization words – sometimes referered to as Search engine optimisation or optimizing for search engines ranking with words) because we need (must or possibly have to) ensure (make sure) we rank (place) for all possible alternative (sometimes known as different) ways of saying (speaking or writing) phrases (or text/words)….

* ALT text should never be thought of as a way to gain better rankings – that is not what it is there for. It is an accessability tool, designed to allow the blind or poor-sighted to use the internet. Over optimising by adding keywords into image ALTs is gonna see your rankings slip quickly.

Cheese & Rice, this article is so full of 2003 it’s unbelievable, and even back then it was bollox.

Derek Halpern

You think bounce rate has nothing to do with rankings? You should do more testing.

Additionally, what you say is 2003 information, a lot of people don’t know because there are people—believe it or not—who are just started on the internet right now.


Tested and Researched thoroughly:

Might be a factor in personalized search, but then if we’re bloggers, looking to rank through images, personalised search is completely moot.

And the 2003 comment – wasn’t a comment on “I am special, I already know this” – it was a comment on “It was relevant in 2003’s search environment – 3 algo updates per day since 2003 – it is no longer relevant, not that it ever really was”


Good rundown of things to remember with images.
I use the GIMP program (free) to do most of my images. It has almost all the functions of large image programs like photoshop.


Where should I put the code for the alt image?

Is this different than filling in the box for alt image in WP? Is this bit of code better?


Sheila Ware

This was a fascinating read for me because I happened across this by chance with my own thesis site. As it is a cartoon/humour blog I do a cartoon with each posting. I had been concentrating on the SEO for the posting, but neglecting it for the cartoon. One day by chance I thought, ‘I wonder if this will make any difference..?’
Suddenly my blog appeared on Google Page 1, Top Cartoon Blog…then popped up all over the Google rankings, even Best Humor/Humour Blog, Pages 1 and 2!
I admit to buying thesis as a complete SEO virgin thinking I needed all the help I could get … now I can absolutely vouch for its merits. Thank you!!



I’d just like to mention that of the many newsletters that drop into my inbox, I almost always read yours right to the end and I think it has to do with paragraph size and spacing. You’re concise, informative and very easy to scan and read.

Thanks, please keep it up.

London SEO Marketing Lab

Hi Derek
You are absolutely right! Many people neglect SEO for images.

I recently updated a website for a client which had multiple image galleries on and his original static HTML website had images named with random names as they were transferred from the digital Camera.

We converted the site (keeping his previous design) to Wordpress but had to address many SEO factors

To solve this problem of SEO for images I used the following techniques:

Wordpress plugin “SEO Friendly images”
This automatically provides the Alt tags based on the image name, but then there is still titles and captions and descriptions….

Well here’s the solution :
we used iPhoto and imported all the photos

Inside iPhoto provided the SEO optimised Title and Description as well as GEO location

Export -> Tick Save using Title as Filename

This will save the meta information into each image.

Then use NextGen Gallery for Wordpress.
to upload a
Zip file containing all the images for a particular gallery

The resulting gallery will be pre-populated with the description and titles for the Gallery, and SEO for images will do the Alt tags for you.

Quick and efficient.

You have to love Wordpress!

Louis Slabbert


Nice post Derek.

I’m interested in the comparative benefits of using Flickr pictures vs hosting pictures on my own website for SEO.

Flickr is becoming tired and I wonder if it is still worth it but there again in the socialmedia world it is good to inhabit many places.


I don’t really use Flickr, so I can’t talk on that for SEO benefits. I prefer to keep all my content, not host it on other sites though.


Very useful post, thanks Derek.

Does the description field have any constructive use for images in Wordpress?

Keep up the great work, I really enjoy (and act upon) your newsletters!


Helpful article Derek and I find your advice easy to follow.
It seems like I forgot about the Alt Text as I was focused on all other aspects you’ve reminded here when I add image in posts within Wordpress.
Future images will have Alt Text properly documented!

As a side note would it be possible for you to add a check box to allow commentators to receive updates on new comments?


Good simple and clear tips for image optimization and useful resources for that.

Would have really liked to understand the different use of Tags & Captions for SEO optimization.

Can one optimize more than one key words on these, or alternate the keywords between filename, Alt text, Tags and Captions

ron chordigian

thanks for the simple explanation…now I know what to do with the images in my posts and how to optimize them…

Fred Siegel

I use a nofollow / noindex rule on all my images because I believe that the traffic images bring is worthless. I want people to visit my site to read the content. I found that 25% or more of my traffic was people using Google image search to find and then steal my images. Like I said my traffic is down but my page views per visit are way up and bounce rate is down because I don’t have that person taking one picture and leaving the site.


hi, thanks for the post very useful. Please I need help. Mi blog doesn’t load pictures on Internet Explorer. I don’t know why.


Love the tip on optimizing your image file name. As long as you’re optimizing the image size for fast load times, you might as well give it a SEO friendly name. Thanks!


Love the tip about captions and file names! Boooyah!

Ana Rose

Article is very informative and just too good.
Its very helpful for beginners.


Great article Derek, missed out on the captions part to be honest. Also jsut submitted myself to be updated by your site SocialTriggers so I’ll prevent to miss this kind of info.


Useful, well thought out information.
Derek took all of us to the next level!
Thumbs up! *pumps fist* p-out.

Sunil Sharma

Thanks Derek for tips. I am confused about image captions, what would happen if caption does not match with post title or alt tag but is concerned with the post. You know sometimes we like to add description of the post or quote regarding the post with image. Does it help in SEO? I follow this practice to engage readers in the post instead SEO purpose. Please enlighten me.

Agrodut Kumar Mondal

How much effective article to link building

Lisa Angelettie

Hi Derek,
I was checking out my site speed with Google Page Speed Tool and saw all these images I needed to optimize to reduce file size. To be honest, I never thought about it. Will be using free tools u mentioned from this point on.


I didn’t know that bounce rate being considered by ranking algorithms exist. Captions ? Yes, that’s the way to grab readers and keep them on site longer. Well, it’s good to know that … and will definitely use these freebies for making pictures smaller. Excellent valuable piece of information. Thank you so much for easily readable and enjoyable article.


Thanks Derek, Though I knew the importance of Image optimization, I was little confusion regarding the File name and alt issue. I got the ans now. Thank you.


The captions part was really insightful, I guess spending more time on a post to ensure good captions and images makes sense now.


Hi Derek,
I totaly agree with you about “ALT” and “TITLE” attribut for a better ranking.
But, I would like to know if renaming a pic “image.jpg” (and all pics of a website) like this “name-of-the-ste-image.jpg” could be useful for SEO and ranking ?
Regards !

Carla Easley

I just started optimizing my site with images on my work at home website. I really appreciate your tips on how to properly optimize images for better rankings.


Hi Derek,

I tried renaming an image by adding (-) between the names and uploading them to the server, but once the image get saved the file name automatically changes to (_) along with a random four to five digit number at the end.

For example,
before uploading to the server the image name was numex-6-pepper.jpg
once saved the image name changed it to numex_6_pepper_5696.jpg

Can you please tell me why is the file name getting changed and will this hamper in Image optimization results in google?

Eagerly awaiting for you reponse.




Great article — CAPTION is the one I know and do not do.

Thanks for the reminder (in short paragraphs) LOL

Sean V.

Excellent post, Derek. I like how you talk about bounce rate– I think we all can sometimes forget that web writing has a greater purpose beyond search results.

I do have a question (actually several!) that I’m hoping you can answer: does natural writing enhance alt tag SEO? Here’s what I mean:


Does writing in full sentences dilute the “SEO juice”? Also, in your opinion, do alt tags hold generally hold more SEO weight than regular text, like headings do? And does placing keywords closer to the beginning of alt tags help as with title tags?

Thanks again for the post!


Sean V.

Woops! The html didn’t show. Here’s the example I was talking about:

img src=”seo-image-optimization.jpg” alt=”SEO image optimization”


img src=”seo-image-optimization.jpg” alt=”Learn how seo image optimization helps improve Google search results!