It has been answered before but I will repeat it because I thought the same thing when I first looked at it.
You are correct, Rating is the scale of 1-5 for that image.
Votes is the total # of votes that image received.
example, 6 people voted for image and it averaged out to a rating of 3.
ratings for this image is 3.
votes for this image is 6 because 6 people voted for it.
not a dumb question at all, it had me stumped till I read it.