I made a mistake with watermarking
 

Hello,
I turned the watermarking to not to overlay image, so it is now permanent.
I made several changes in categories and moved images from one category to the other.
Could I upload a backup of the images folder to the server and so "undo" the watermarking? or are those images also marked as watermarked at the db and since then they are going to be unwatermarked in any way?.
have the category moves a reflect in directory locations?

If you upload an backup of an image that is not watermarked then the files would be unwatermarked when you view them. The database field would still be set to yes but is there to prevent a watermarked file from being rewatermarked. You can alter the field back to no if you want.