Image palette in object editor got reduced and I can't reverse it.

[Brick Nash]

Ok folks I may have made a boo boo and I can't seem to fix it.

I was grabbing images into the object editor and all of a sudden the palette for every single image was reduced down to the first 16 colours of my original 64 colour palette. I've no idea how it happened but I'm a bit panic stricken in case I made a major error and the images are ruined.

I still have one image in the bank that has the correct palette but I've no idea how to apply it to all the other images.

Any advice?

EDIT: That's twice it's done the same thing today totally at random. Never happened before so I'm stumped. Thankfully I have a backup this time but I really want to know what's causing this as it takes so much time to re-grab all the frames.