Is it illegal to draw and sell a stock photo?

I recently found a gorgeous stock photo from 123rf.com and I drew the photograph and people are interested in prints of it. but I don't if I should because I first would like the permission from 1 the photographer or model in the photograph. The photographer lives in russia and I sent him a message about everything about a day ago but could only send it in english. I would really love to sell my portrait. but would first like his consent. If I chose to sell the portrait will anything happen? would it be called copyright infringement? please help!!!