It's my understanding that the images are indexed in relationship to the text that is near the image. It also depends on the title and alt tag associated with the image.
Yep, my images have all the necessary, I'm also talking about seriously weird things like in Google search preview when some regular pages show all the images including AdSense and other pages do not show a thing, not even the company logo.
It makes me wonder if something is badly broken since they do not seem to know what they have themselves.
It's not just me, I have competitors asking me what's happened since many of their images have also disappeared meanwhile my images are appearing on some very strangely addressed sites with no alt, no title, no product description etc, the only thing is a copy of my image with the keyword image name which makes a mockery of all my work and the supposedly correct W3C way to do it.