It gives your image files descriptive, SEO-friendly names based on a template (for example summer-dress-my-store-3123098.jpg). Renaming runs together with compression or squaring and doesn't cost an extra action. It's available on paid plans, and the template takes effect once you save Settings.
Renaming changes the image's URL, and that change is permanent — restore brings back the image content but not the old file name.
Not sure renaming is right for your store? Chat with us before you turn it on.