The most important tip:

Rename your images file to long tail keywords you want to target

Eg: long tail kw1 :a big hairy gorilla
long tail kw 2: big gorilla with hair

rename your image to: a-big-hairy-gorilla.jpg
remane title and alt text to big gorilla with har

Do this with all the images on your site.

Thats a basic outline of how I dominate images.
( ong tail keyword research is critical)

You can also upload the images to all file sharing/image
sites and ensure that you WATERMARK these images
with your URL