Mongodb或Mysql哪个适合存储图像链接和关键字

I am working on a django project which shows images the db will have image links and descriptions(keywords) i dont want duplicate entries in the imagelink which is the best database to use with it? shall i go with mysql to avoid duplicate entries? but i realy like the json structure of mongodb it is easy to handle i think Please suggest a good one I am working on a django project which shows im