How To Remove the Lines and Boxes On A Form?

[Blighty]

(11-18-2018, 09:33 AM)Espermaschine Wrote: I know that Photoshop has a functionality that aligns images automatically, so maybe there is a script for Gimp that does this, or could be written.

Not automatic, but Ofnuts has layer aligner that works well and easy to use.
ofn-layer-aligner , available here:
https://sourceforge.net/projects/gimp-to...s/scripts/

A much easier method that may or may not suit the OP is to select the black with the Colour Select Tool; and then paste as a new image. The difficulty comes with the edges of the black where the black tends to fade into a gray. Play with the Threshold to see if a suitable result can obtained. Worth doing a bit of experimenting.