There's some code here from my code archive entry to read the ARGB and recombine and write back.
http://www.blitzbasic.com/codearcs/codearcs.php?code=1013
Hope that helps a little. I take it you know .jpgs have visual quality degradation when they are saved? There kinda bad for stuff where all the pixels need to retain there exact values.
http://www.blitzbasic.com/codearcs/codearcs.php?code=1013
Hope that helps a little. I take it you know .jpgs have visual quality degradation when they are saved? There kinda bad for stuff where all the pixels need to retain there exact values.