I'm summarizing what I believe to be the most important elements in (hopefully) getting important images, graphs and photos to rank:
- File names should include the keyword phrase(s) the page is optimized for
- Include keywords in the Alt Attributes tag
- Where possible include descriptive text or captions around the image
- Allow engines to index your /images directory
- Images should be optimized for optimal download times
In Google's main index I rarely see images appearing as a search result; so I'm interested in understanding if going through a large site to make these changes is worth the effort. Of course we wouldn't do this for all images - but selected images of such items as illustrations and products.