I sometimes go through the "new" section of #photofeed and upvote the photos I like and I think that many others are doing the same :)
But nobody should expect to earn more for a photo than for a really good blog post that incorporates a lot of great photography. The problem is, that many lesser-known authors have their posts sitting at a few cents, no matter if they post a single photo or a longer blog posts.
I might be bitter... but what I see is that only the curation accounts (and competition accounts) benefit from the upvotes for the photos. This is of course a generalisation and exceptions are always there.