If you want to do it legally they have to be your own backups.Oh, okay! That makes more sense. I can dump GBA, DS, 3DS, & Wii ROMs. For the other games I own, is it legal to use someone else's backup, or do I need to find a way to dump those?
Also, in the US, it could be argued that often the dumping process violates DMCA because it requires circumventing copy protection. DMCA is kind of vague on exactly what constitutes circumvention, and I have yet to hear a court ruling that goes one way or the other, so it's not exactly clear. I assume they mean cracking or otherwise circumventing DRM, and console games don't really have DRM, they are simply difficult to copy due to the medium they're stored on, or due to DRM in the console itself. Which also means that it could be argued that it's illegal to install CFW or backup loaders on a console as that would also circumvent DRM. But I have yet to hear anyone actually being prosecuted for it. Also emulators don't have DRM to begin with so those should be fine.