Image Optimization
Make sure at least one image file name includes your target keyword (for example, on_page_SEO.png) and that your target keyword is part of your image Alt Text.
BRIAN'S TAKE
Another reason to optimize your images for SEO: it gives search engines another clue of what your page is about…which can help it rank in organic search.
When Google sees images with alt text “blue widgets” and “green widgets” it tells them: “this page is about widgets”.