IrfanView is a free image viewer with a simple way to crop, but it's also an image viewer, but
free to use.
At least I crop my images, except the Romancing SaGa scans I added. I didn't when I first scanned them and just didn't feel like it when I came around to adding them.
Also it seems like the list is outdated for scans to be 'upgraded' slightly. I know I added the Grandia Povo & Deus scans, except I didn't replace the cover, but it was probably fine to leave it since the edit was oct '09 and I added them pretty recently. I think the quality is fine, too. Maybe someone should update the list as I don't mind scanning to add if I have the album sometimes (though it's just lazy for me not to go through it myself to see what could be added).