SEO Image Optimization

When you read about SEO image optimization, you almost always get the same advice: Use keywords in the image file name and the image alt text. None of these articles tell you that you can actually rank well without putting keywords in the file name and alt text. In this blog post, you’ll learn about the factors that will really help you to improve KPIs.

But what about naming images for SEO?

It certainly doesn’t hurt to put keywords in your image file name and alt text. This will not prevent your image from ranking well, and it might still be beneficial when combined with other factors. So go ahead, use your page’s primary keyword phrase in your main image’s file name, separated by hyphens. Use the same keyword phrase in the image title and the image alt text, without hyphens. Needless to say, file name, image title and alt text should accurately describe the content of the image.

Other best practices that seem to be beneficial are using jpg as the image file format and keeping the file size within in 40-70 KB range.

What could be more important than image file name and alt text?

Engage took a close look at top-ranked images in Google Image Search. What we’ve found is that contextual factors are much more important than the best practices for naming images for SEO that are mentioned above. It is entirely possible to be top-ranked in Google Image Search with images that do not use keywords in the file name and alt text.

What really matters is that the keyword phrase for which the image needs to rank well is used in the text surrounding the image, preferably within 25 words before or after the image. However, the keyword phrase should also be found in the page URL, page title and headline. This tells and confirms to Google what an image is really about. In other words: If a page is overall well-optimized for a specific keyword phrase, an image from that page also has a good chance to rank well.

This perfectly aligns with Google’s Image Publishing Guidelines: “Whenever possible, place images near relevant text.”

Google also encourages the use of structured data for images that are related to products or recipes.

Don’t think about rankings, focus on page speed

Much more important than ranking well in Google Image Search should be the user experience, especially on a mobile device. Except for an overuse of JavaScript and tracking codes, images are usually the main culprit for slow site speed. If users have to wait too long for a page to load, they will go back to Google and click on a different result. Since Google prefers not to rank pages with such a poor user experience, page speed will be an important ranking factor with Google’s mobile first index.

The most common issue we see when we perform SEO audits for ecommerce sites is the resizing of images in HTML. This makes image file sizes much larger than they have to be and slows down page load time significantly and for no good reason. Therefore, your SEO image optimization efforts shouldn’t focus on naming images for SEO or ranking well in Google Image Search, but in reducing file size and improving page load time. This will affect KPIs like number of visitors and sales much more than any top rankings in Image Search.