I am currently working on a site with 100+ recipes that all have image file names that are relevant, but not optimized for keyword purposes. I'm wondering - from an SEO perspective - would it be worth my time to go back through all of the images and rename them with keywords in mind? On my own site I have always done this as a "best practice" but I'm curious - does it make a difference to search engines? Does anyone have any recent research/experiences that they would like to share? Thanks!