Like most things in Search Engine Optimization, you can always be trying and testing something in an attempt to get an edge on your competition in the search engine rankings. Two areas where SEOs commonly have room to improve are image search and page load speed. However, some effort and know-how in both areas is required, and chances are not everyone has what it it takes. This is why you may be able to get a leg up on your competitors if you’re willing to take the time to learn. And because image optimization is inherently linked to the improvement of page speed, and conversion rate increases when page load time decreases, you’re almost guaranteed to see a return on your investment.
Optimizing images is a task you’ll need to repeat again and again in a consistent way in order to reach your end goal of faster page load speed and increased visibility in the Image SERPs. As with any repeated effort, a checklist is an invaluable tool to getting the job done right every time, so I’ve put together a set of checklists for optimizing images and page speed elements related to images. The checklists are the culmination of the some of the best advice from industry experts I’ve turned to during my own research, which I’ve collected and categorized for you as Beginner, Intermediate and Advanced. These classifications refer to both the aptitude level required for implementing the recommendations as well as the general order in which they should be tackled. You’ll find examples and resources along the way and a link to download the checklists for yourself at the end of the post.
1. Test your webpage’s page load speed
It’s important to establish a benchmark of your performance in both Google and Bing so you know if you’re successful later. Use Google PageSpeed Insights and GTmetrix (or Pingdom or Web Page Test, whichever is your favorite.) Because image optimization takes time, you’ll want to make these changes to a small number of images first to see if your efforts have paid off. We recommended changing one element (like adding alt text) per batch of images at a time and re-testing after each type of change so you can empirically track the effectiveness of each step. The good news is, you’ll be able to test the effect on page load speed more quickly than traffic from the Image SERPs, so you’ll get some immediate gratification.
2. Choose the right format for your images
As a general rule, GIFs and PNGs are best for small images with a limited palette, transparency (and animation if needed) like logos, icons and design elements. JPGs are best for photos with a wide palette of colors and a lot of detail.
3. Resize images to a unique size
This is particularly important for ecommerce websites. Of course, it’s best to use your own original images, but when that’s not feasible and you’re using the same images from the manufacturer all your competitors are using, create a unique sized image to enable the possibility of your image appearing in the Image SERPs. Don’t have Adobe Photoshop? You can edit photos with free tools like Pixlr or Gimp.
4. Serve scaled images
When you serve up images that are the exact size you want the image to display on your website, according to your CSS and HTML, you eliminate the overhead it takes to ship extra pixels from the server only to have the browser resize the image for you.
5. Reduce quality to the sweet spot
The sweet spot is that point where the file size is as small as possible without sacrificing naked-eye perception of quality. The larger your file sizes, the more time it takes for the page to load and the more data it takes. Your users — especially your mobile users — will be negatively impacted by either a data usage fee, or by not being able to load your site, which means you’ll be hurt by a bounced session.
6. Change your filename
Name your image something descriptive, accurate, not keyword-stuffed, using hyphens for spaces and all lowercase letters. Intuitively, it makes sense that an image filename adorable-baby-bunny.jpg will rank higher in the Image SERPs than file4601256720423.jpg for a relevant query.