But I have one update. When GIMP is open, and you click on a .xcf file which is set to open via GIMP as default... Each file you click on in the file manager, will open a whole new GIMP. Thus if you've opened 1 image, then decide you want to open anotehr image , the old iage open will stay there, but the new one will open anotehr instance of GIMP, and then you have to switch back and forth between GIMPs to work on the images.
This didn't happen in previous KDE 4.10.X, and doesn't happen in XFCE. I'm not really sure if it's a bug in KDE, or a setting got changed when upgrade went in.
This doesn't really affect KDE per say, but does affect user efficiency. :/