Ciao, @Pietro_Dolcini, and welcome!
I agree with the advice you have already received about using xfce as your desktop environment. It is light-weight but effective.
Distros are great fun
Presently I use Manjaro/KDE, and I like it very much. In your case, I would say Manjaro/xfce. But you have to remember that dIstros are really a personal matter… ask 15 forumers and you will get 19 recommendations…
As far as I remember, there are (have been?) two photo/graphics centric distros: Ubuntu Studio, and fedora Design Suite, but I believe that both would be overkill in your case.
Cordiali Saluti,
Claes a Lund, Svezia