There are lots of different searches out there. Ours is just one and runs on our own rules. Comments, favourites and likes help raise the image in searches here
Google, and the other 20 or so searches who index us, don't use likes comments and favourites as they are internal
Yes, commenting on your own images will raise awareness of them in the activity and yes, this may... And the operative word is here is may, show them up to indexers off site, but the activity again is more internal. It will show on anyone who is following you so will remind them of the image, which may, in turn, bring more comments...