Images are important to SEO — if done correctly, they’ll show up at the top of Google Images and link back to your site, bringing you a ton of traffic. To help achieve higher rankings for your site, here are some SEO best practices recently published by WP Engine - a website hosting service I use for many of my clients' business websites. ~ Kenneth Greenberg :: WordPress Webmaster
Naming Your Images
Google’s ranking algorithm calculates images, so properly naming your images can help your site rankings. Before naming and uploading an image, you should first decide on a proper keyword to use.
In the image’s filename, you should include relevant keywords from a specific subject. Instead of uploading your image as “IMG_6594. JPG” try using a keyword rich name like “Lionel-Messi-ArgentinaSoccer” if you have a picture of Lionel Messi playing soccer for his home team. (You could also add in the term “Football” or “Futbol” to get more global reach.)
It’s also important to use dashes ( - ) and not underscores ( _ ) when separating keywords, as Google looks at underscores as a joiner of words, rather than a separator.
In addition, be sure to include your main keywords at the front of the file name, not the end. Compress Images For Faster Load Times Images can be the culprit to a slow site, as they make up around 60 percent of a page’s size. Therefore, optimizing your images for web upload will speed up page load time, ultimately preventing Google from penalizing your site rankings due to slow page load times.
Images that load faster due to being optimized for web will make your site load faster, and in return give you better SEO.
Give Your Images Alt Text
Alt (alternative information) text was originally intended for the visually impaired, but is also used by search engines to interpret what your content is. Since search engine bot crawlers cannot technically “see” your images, these fields act as clues to what your visual content contains.
The text you use in the alt text section will help search engines understand the context of your image. Therefore, your alt text description should be as accurate and descriptive as possible, and contain your main keywords. Think about how you would describe the image to someone who is visually impaired?
A better user experience = better SEO = more traffic = increased bottom line.
Understand The Differences Between Alt Text And Image Titles
Title tags and alt tags are commonly confused with one another. Let’s take a look at how they differ… While the alt tag is used by search engine crawlers to determine what your content is, title attributes provide extra information about the subject and are not crawled by bots. Therefore, image title tags aren’t as important to your site’s SEO, however they do result in an improvement of accessibility online.
If an image is missing, the alt text will show in its place, however the title text appears in a popup in certain browsers when a visitor hovers their mouse over the image.
Choose Unique, Compelling Images (And Test Them)
Try to avoid cliché stock photos as best as possible. If other sites are using the same photos as your site, why should yours rank and theirs not?
It’s important to set yourself apart by using high-quality, visually stunning, and unique imagery that doesn’t fall into the “I’ve seen that a dozen times already” category. If possible, shoot the photography yourself, which will help with brand identity and also be more likely to rank higher.
However if using your own photography is not feasible, there are plenty of free stock photo options out there. Flickr.com has creative common images you can use, and there’s also these free stock photo options, most of which don’t require attribution.
Now that you’ve decided on an image, how do you know if it will fare well with your clientele and site visitors?
There is no exact science to this, but you’ll want to monitor it over time to see which images perform the best with your audience, and develop insights about that data.
One example is to test images on social media to see which visual gets better engagement. Just be sure to keep all other variables the same so it doesn’t distort your data. For instance, the social text and headlines shouldn’t change between images. Also be cautious of the time and day you post something, as that could factor in with a higher (or lower) engagement.
The more you test images and develop insights, the better your taste will become for good photography and visuals that perform well and rank higher on Google.
XML Image Sitemaps
If you’re on WordPress, these plugins can help you create a sitemap: Google XML Sitemaps, Yoast SEO, All-in-One SEO Pack, Udinra All Image Sitemap.
For non-WordPress sites, there are many tools that can assist in creating a sitemap, including: Screaming Frog, Dynomapper, and more. Once you’ve created a sitemap, you’ll then want to submit it through Google’s (or other search engine’s) webmaster tools.
The placement of visuals within a blog post or web page can make a significant impact on how it ranks on Google. If you place an image closer to the search text, it is likely to rank better. Also note that adding a keyword rich caption to your image counts as search text and can help with better image SEO. Just don’t overdo it on captions, unless it adds something valuable to the image.
Along with these essential tips, keep in mind that a page that ranks higher will result in higher ranking images. Therefore, you’ll want your main keyword to be peppered throughout the page, including the title, header (e.g. H1, H2…), URL, and within the body of the text. But be sure not overstuff your content with the keyword...only use it where it makes sense.
Search engines use the context surrounding the image to better dissect what it is, so if you place an image somewhere and the context isn’t relevant, then it is less likely to rank.
Once you incorporate these image SEO strategies into your content workflow, you should start seeing improvements in the quality of your content and search engine rankings in no time.