Paint.net
Quite simple, but you can get loads of add-ons from the pdn forum if you feel like going crazy.
(
Colonel Boris "...a desperate Buzzfeed imitation...",
Sun 19 Jul 2009, 15:32,
archived)
^This
Worked well enuf for me.
(
FeralCatMan Long ads need comments sections,
Sun 19 Jul 2009, 16:57,
archived)