How do I load PNG file, modify it and then save as JPG without corrupting the original colors?
See here Java JDK1.4.x example program with source. I'll appreciate all the comments (see email in readme.txt file).
example program

Output examples from test program:
Original picture:

Saved as png, looks ok:

Saved as jpg, corrupted colors. Browser cannot display it, but GIMP and windows image viewer will open it:


Here same picture "saved as" in GIMP. See bad colors:

This code should fix the problem. Point is to use _RGB format, not _ARGB when saving a jpg files.