I made this tool to easily extract the graphics from the game "Yu Yu Hakusho - Bakutou Ankoku Bujutsukai (J).nes", the graphics are in the chr ram, and they use an RLE compression algorithm. Use yychr or any graphic editor for edit, then compress again.
Synopsis:
yyhbab2bin.exe [-d | -c] -- decompress --compress
If you need edit the texts use: https://github.com/KodingBTW/yuyuhakushobabnes-translationtool
ROM name has to be "Yu Yu Hakusho - Bakutou Ankoku Bujutsukai (J).nes", place extarctor in the same patch, open console and write "yyhbab2bin.exe -d", extract bin, then edit bin files. put "yyhbab2bin.exe -c" to compress again.
Of course, there's no need to ask. Feel free to use it in your project. I only ask that you mention me as contributor.