Image Optimization 101

SMS Text

SEO can be, at times, overwhelming to its practitioners. After all, there’s nothing easy about designing and carrying out an effective link building strategy, or about adjusting any of the dozens of on-site variables that play a role in your website’s natural search performance.

Considering how prevalent this mindset is, it’s important to take a step back every so often in order to focus in on the short-term techniques that can be carried out in order to bring about positive SEO results as quickly as possible. Image optimization is one of these processes, which can be completed in a few hours or less, using the following steps:

Step #1: Obtain Images From Legit Sources

Before you can even begin the on-site image optimization process, you’ve got to find the images you’ll use in your blog posts, Web articles, and design files. And here’s the deal: Despite what some unscrupulous webmasters would have you believe, simply popping over to Google Images and searching for image keywords that turn up the type of pictures you’re looking for aren’t effective image sourcing!

Be aware that doing so may put you in violation of Internet copyright protocols, which assign all creative rights to image artists—unless the artists themselves choose to release some of these rights under the Creative Commons license. If you’re caught with unlicensed imagery on your website, the original creators of these pictures are well within their rights to ask you to remove the images and to pursue legal action seeking damages if you fail to comply.

So, when it comes to sourcing images for your website, you’ve got two options:

  • Pay for stock photography through sites like Fotolia, iStockPhoto, or PhotoXpress.
  • Use images to which the original artists have released some rights to webmasters.

If you choose to go the second route, you’ve got a few different options for finding images that have been released for use under the “Creative Commons” license. My personal favorite, however, is to go to and use the site’s Advanced Search features to pull up only Creative Commons licensed images (though even if you do take this route, you’ll still need to follow the artist’s instructions for providing proper attribution to any images you use).

Step #2: Resize Your Images Before Uploading Them to Your Website

Now, once you’ve got your image files downloaded, one of the best things you can do to improve your on-site image optimization is to resize your pictures to the precise size needed for your website before uploading them to your pages.

Here’s why this is so important…

Most website owners simply upload their original files and then control the size at which these pictures display by modifying the “height” and “width” parameters of their image source code. And while this might be easier to do on the fly, it means that your original, much larger image files are still hanging around on your server, taking up space, and putting an extra burden on website visitors’ browsers to resize these files whenever they’re loaded.

Essentially, when image files are set up in this way, the browsers that display them must first load up the larger files, then read the code that determines what their display size should be, and then resize the pictures for the designated display.

All in all, this extra effort—compared to simply resizing image files before uploading them—translates to slower load times, which counts as a negative against your website’s SEO. Google has emphatically stated that it wants to reward fast-loading sites, which is why taking the extra step of setting image files to the appropriate size up front is so important from an image optimization perspective.

Step #3: Save Image Files Using Keyword Descriptions

To edit your images to the appropriate file size, you’ll need to use an image editing program like Pixlr or SnagIt. And, while you’re in there, take the time to change your picture’s file name to your target keyword, which will add another tiny boost to your overall image SEO.

As an example, if you’ve downloaded an image file that’s named img_098234029384.jpg, renaming the file to read target-keyword.jpg will improve your image optimization. At the same time, it’ll make it easier for you, the webmaster, to manage the existing files on your Web-hosting account or server. It’s a win-win for everybody!

Step #4: Update Your Image’s ALT and Title Tags

As you upload your modified image files to your website, take care to update the ALT and title tags associated with each of your pictures according to image SEO best practices.

Now, contrary to some opinions, this doesn’t mean slapping an ALT tag on each of your images that’s structured according to the following formula: “keyword 1, keyword 2, keyword3 , etc.”  That’s just an over-optimization penalty waiting to happen!

Instead, think about the original function of the ALT and title tags associated with website images. In fact, these tags weren’t created to give over-eager webmasters an extra chance to cram their keywords into the hidden nooks and crannies of every site. They actually came about so that website visitors using adaptive technologies (for example, visually impaired visitors using screen reading software) could make sense of all the content found on a webpage.

Take a cue from this original intention when it comes to optimizing your image ALT and title tags. Sure, go ahead and use your keyword phrase where possible and when it can be done without seeming forced. However, do it in a way in which your keyword is couched in a descriptive phrase that provides additional information to any and all website visitors, rather than simply stuffing these tags full of target phrases because there’s some SEO benefit associated with doing so.

When done correctly, adding appropriate tags to your website images can have two benefits. Not only does proper optimization support your site’s overall SEO (making it more likely to rank highly in the SERPs for your target keywords), you also stand to gain new Web traffic from the picture files on your website appearing in the Image Search results found around the Web.

Again, it’s a pretty great win-win for webmasters who are willing to put in the short amount of effort needed to carry out proper image optimization.

Step #5: Add a Caption to All Website Images

One final step that you’ll want to take when it comes to enhancing your site’s image SEO is to add captions to your website images wherever possible.

While this isn’t exactly a known SEO ranking factor, be aware that image captions are amongst the most-read pieces of content found on any website. Our brains naturally gravitate towards images, and once we’re there, we often feel compelled to read the text associated with these pictures.

As such, the content you add to your website image captions shouldn’t just be plain old text. If you have a point you’re trying to make with the Web content your pictures are associated with, do it here. This might mean filling image captions with the main points of your blog articles, with calls to action based on the area of your site in which they’re used, or even instructions on steps that your readers should take next. Whatever course you choose, just be sure you’re not letting this valuable space go to waste.

Again, the SEO implications of this practice don’t come from Google assigning a benefit to the presence of your target keyword in your image caption text (though this may occur, as well). Instead, know that Google values metrics like time on site and user engagement—both of which can be measurably increased by capturing reader attention with the use of effective image caption tags.

For all this description, the actual process of image optimization can be carried out fairly quickly, depending on the number and complexity of the picture files used on your site. If you have an extra hour or two on every given day, following the steps above can be a great way to give your site the fast SEO boost it needs to perform even better in the natural search results!

Sujan Patel
Sujan Patel has over 12 years of digital marketing experience and has helped hundreds of clients increase web traffic, boost user acquisition, and grow their businesses. He’s currently the VP of Marketing at When I Work, the top rated employee scheduling software. In addition to his role at When I Work Sujan co-founded and wrote the book on Growth Hacking titled 100 Days of Growth.
Sujan Patel
Get the latest news from Search Engine Journal!
We value your privacy! See our policy here.
  • Ivo

    Thanks for the article, Sujan! Never thought of using the captions to improve the SEO of my images! I’ll definitely try it out!

  • Pankaj Sharma

    Thanks for the information but i have many questions , as i am new in seo.
    1. As you mentioned , if i search a image in that and copy that to my blog with changed attributes like if the image is of 230*300 size then i re-size it with 200*250 and change the name and also give some effects .Now if i do this whole process then i think i am not violating any of Internet copyright protocols? Please guide.

    2. Fotolia, iStockPhoto, or PhotoXpress what are these sites are they paid . Will they make photo for me or what?

  • Mike van der Heijden

    Great re-cap for image optimisation. It’s amazing how many times I see websites without any optimisation done on images. Thanks Sujan!

  • Joydeep Deb

    I would like to include couple of more points/tips

    – Always use WIDTH & HEIGHT for all the Images (helps the browser to render faster)
    – Crop unwanted white-space from the images (helps in reducing file size)
    – Add an Expires or a Cache-Control Header (at least for 1 month)

  • nick d

    Good tip about the image caption. I’d not thought about that (also).
    I think the general theme of page helps as well. One little thing I’ve noticed is that the SEs are very good at string parsing, eg in urls – the same probably applies to image file names as well; ie it can read ‘thisismyfilename’ and understand it where ‘this-is-my-file-name’ has obviously been seo’d – and we know who doesn’t like that at the moment.

  • Kate

    Thanks for the post! Does anyone have any advice for organizing a large quantity of images – originals and resized for web? I found the easiest way is to keep the original file (ex. ‘original-photo.jpg’), then I make another one smaller for the web (ex. ‘original-photo-for-web.jpg’), so the two photos can be right next to each other for easy access later on. But that’s not good for keywords in the photo name and it just looks tacky.

    Someone else suggested keeping a folder separate for the web-sized images but then I forget where the original was and/or forget which ones are on my website when I’m searching through photos to add something new.

    Any personal experiences with this that anyone would like to share? Thanks!

  • Matt Coffy

    Thanks for sharing these important notes to remember, Sujan. I wouldn’t be too sure by asking this, but how about those infographics, would Step #2 apply? More often than not, I encounter hard to read infographics and clicking on the image would direct its reader to its link however, the image has then become even smaller. I would instead expect that the image would be bigger and clearer.

  • Ashok Padhye

    Excellent points Sujan and Joydeep. I would like to add one more – when you resize the photo, always make sure that the aspect ratio is preserved, else a slim lady may appear like one who sings at the end of an opera.

    Does anyone have any comment about the point made by Nick? Would the you-know-who really penalize this-is-my-file-name.jpg instead of thisismyfilename.jpg? The one separated by hyphens makes for much better readability and manageability, which, to my mind, is a legitimate reason to be using that as a convention and so, should not be penalized. But I would like to hear what experts say.

  • Navjot Vashist

    Good steps of image optimisation, Thanks for sharing

  • Richard Ng

    Hi Sujan,

    Great tips on image optimization, I often omitted the image caption part. This will serve as a reminder for me to do it in the future.


  • Meagan Sutton

    There are a lot of great tips here. I agree that SEO is not always an easy task. This remains especially true when you have international image SEO going on. With so many languages on the web, it’s important to know your audience. Keywords, and photo captions, not only have to be content relevant, but also translated and localized. Images themselves must also be market appropriate in order to avoid confusion. Without culturally accurate content, domestic or international, targets might be missed.

  • Ctc

    A very useful WordPress plugin to proper Images attribution – Credit Tracker