I agree that this would be helpful. Whenever one of my photos gets negative votes, I sometimes ask myself "Why?".

An alternative would be to at least know whether the points removed were for the quality or the relevance... or both. In fact this information would also be useful in the case of positive votes.  :o)

I think that comments are a fundamental feature for any site that want the members improve their skills and the quality of the pictures. Get a glance to photo.net and you'll understand perfectly that this is true.

Mauro

If I could see the comments I'd understand (perhaps !) how a picture can get 12 points and be featured in an article and get -5 points in another article ... when relevancy can't be the reason :

http://www.fotopedia.com/wiki/Orange_(colour)#!/items/charlottes-b_2UVtoXzIk

http://www.fotopedia.com/wiki/Pyracantha#!/items/charlottes-b_2UVtoXzIk

I do NOT like the idea of giving comments on your down voting.  The whole voting system is a subjective, because there no objective way to rate quality and even relevance.  For one person a photo is good for the other one it's of quality.  The overall rating will say "something"  on the average quality of the photo, nothing more and nothing less.  If I go through an article I vote on pictures I like, and I vote down on picture I don not like.  I do not like the idea of giving comments.  Looking to for example 500px, you see mostly positive comments as "great", "beautiful", "nice".  I suppose don't want such a system. If we all accept that our most beautiful pictures can be judged differently by others I don't see an issue with voting.

One of the useful opportunities Fotopedia provides is to help people understand how to choose better photos to submit. Negative points without comments don't help that much at all. Also, requiring comments serves to make someone think a little more before negatively voting, which is not a bad thing. 

Sure you may get unhelpful or lazy people who are too vague in their comments, but you'll also get plenty of people, I'm sure, who do provide useful explanations.

I don't think, by the way, you should be downvoting photos just because you subjectively dislike them. I think downvoting should be related to identifiable technical problems with a photo. If you just don't like it, then just don't vote for it.  A key issue with downvoting on such subjective grounds is that the photos only receive a small  number of votes on average. If you could expect a photo to attract 50 voters on average, i'd probably not be worried, but when good photos are getting 5 to 15 votes from presumably even fewer voters, a negative vote based on subjectivity has a significant effect that may not be properly balanced out in the long run.

Every vote is subjective - every flag is subjective - every featuring is subjective - objectiveness is non existing in photography.  Why is there a down vote button?  In my view to use it.  Pictures that have identifiable technical problems need to be flagged?!