images rejected for technical reasons, can you give me your opinion?

bonjour, toutes mes images ont été rejetées sur fotolia pour raisons tecniques mais acceptées sur d'autres microstocks, pouvez vous me dire ce qui pose problème

je pense que c'est la résolution que j'augmente artificiellement, certains élémentss d'origine composant les images étant à 72 dpi?

hello, all my images were rejected on fotolia for technical reasons but accepted on other microstocks,

can you tell me what is problematic?
I think it is the resolution that I increase artificially, (most of them have 600 dpi and 4mb pixels when i posted it but some original elements composing the images were 72 dpi

I still have the right to 6 submissions and after it's dead! here are some avatar of my images

and here are the next i wanted to submitt (if possible i prefer to have your opinion first)

thank you for your help