I am developing an application and my team are advertising on it in Facebook, Instagram and Google plus. We are sharing creative and beautiful images in these networks, but unfortunately we don't see them in the google images.
I searched and figured out that Instagram doesn't let Image Index with "noimageindex" meta tag. Facebook prevents indexing with robots.txt file.
Only Google plus indexes the images, but there is no "alt" attribute for none of them, so images are not shown at the top of SERP.
So it seems like there is no chance that Google ranks photos published in social networks in the first pages of SERP. Is it right?