I was looking for rogue games and a link from a rogue game, gived me this, rexpaint :
rexpaint
Edit characters, foreground, and background colors separately
Draw shapes and text
Copy/cut/paste areas
Undo/redo changes
Preview effects simply by hovering the cursor over the canvas
Palette manipulation
Image-wide color tweaking and palette swaps
True-color RGB/HSV/hex color picker
Create multi-layered images
Zooming: Scale an image by changing font size on the fly
Browse art assets and begin editing at the press of a button
Images highly compressed
Export PNGs for use in other programs or on the web
Export .ANS files for ANSI art
Other exportable formats: TXT, CSV, XML, XPM, BBCode
Import .TXT files
Skinnable interface
The forum of the rogue game Cogmind, developer Grid Sage's :
http://www.gridsagegames.com/forums/index.php?topic=13.0
If it is worth it, you can stick it.