I program on the NDS and although I'm not totaly sure what you asked, I'll just yadeeyadeeya some basic info about graphics.
Images are converted to RAW files using
GRIT or gfx2gba (mostly GRIT, as this is integrated in
DevKitPro). They support the use of metatiles and convert the image in either tiles(2, 4, 8bit) or bmaps (usually 16bit). Tiles can have 16 times a 16bit palette, or one time a 256 bit palette. Bmaps can internally have a maximum size of 1024x512 when in 8bit mode. Transparent color is supported, but AFAIK only one color. No antialiasing.
Here is some more info about graphic modes:
http://www.dev-scene.com/NDS/DOCgraphicmodesThe people in #dsdev on irc.blitzed.org (neat IRC channel with lots of knowledge) would all recommend you
programmers notepad as development environment, but it's just your own taste. Most people use libNDS to make programming on the NDS easier for them. A bit older library is PALib, but you'll be laughed at in the IRC channel when you use it

. They both are included in the devkitpro package. This chaintool can be used for developing on the NDS, GBA (which is also implemented in NDS) and PSP... perhaps even more.