NGGTool

"Neo-Geo Graphic Tool Suite" by evo.

Found as an archive including 4 executables and a text file.

Decode.exe and Recode.exe are used for sprite tiles, decode8.exe and recode8.exe for fix tiles.

The decoders take two C ROMs or one S ROM and output a 4BPP SNES planar type file compatible with YY-CHR and Tile molester. Recorders do exactly the opposite.

Warning
It seems recode8.exe is broken, it inverts some color indexes:

Normal Converted 0	0 1	1 2	2 3	5 4	3 5	7 6	9 7	B 8	4 9	8 A	A B	C C	6 D	D E	E F	F

This isn't a problem when editing existing ROMs without knowing the palettes, but becomes one when importing converted graphics.