In other posts I made some references to my most used software to repair photographs. The following link takes you to see some of my work in progress.
I use Gimp to repair damage, Darktable to correct color and exposure, and Digikam to manage my photos.
None of the above software really is suitable for the pure beginner but... the truly interested can find tons of tutorials online.
Digikam caveat... If you install you will find it has a ton of KDE dependencies. Also, it's a heavy user of memory and processing power. To date, on this machine, VSIDO has been the only distro to run it without crashes!
btw... (haven't tried it on the #! machine)http://jrmweb.com/WIP/index.html