True artists take criticism with a grain of salt; it's an opportunity to learn from our mistakes and to improve our craft that applies for all aspects in life. If I see an image that I like I give them a good comment, but if I see something wrong with it, I tell them. But I also have noticed some folks give the usual "good job", "great image" even if the image sucks donkey butter, as a community we all have to stop doing this, if somebody does something wrong in an image, or the Poses look stiff, or the expression looks bland, we should tell the artist, so he/she is aware of her mistake, and is able to fix this and improve his/her style.

We have to stop being afraid of hurting people's feelings and truly criticize in a tactful informative manner.

Ask me a question, and I'll give you an answer.