GIMP
GIMP is one of many in the List of applications/Multimedia#Raster editors.
Installation
Tip: The GIMP implements a plug-in system and the repositories (official, AUR) contain more plug-ins than listed in the package's optional depends.
Troubleshooting
GIMP PDF editing doesn't work
GIMP requires the poppler-glib library for editing PDF files. Without this library GIMP will say that a PDF file is "unrecognized" when an attempt to open a PDF is made.
See also
- Wikipedia:GIMP
- debian:GIMP
- Resources | GIMP Magazine - Index of GIMP resources, tutorials, communities