This article is from the Mac Programming FAQ, by Jon Watte firstname.lastname@example.org with numerous contributions by others.
The format of a picture resource version 1 is defined in a technical
note. This format is obsolete.
The format of a picture resource version 2 is defined in Old Inside Mac
vol V, with addenda in Old Inside Mac vol VI.
Some things happen with QuickTime compressed pictures; try the Inside
Mac: QuickTime book or turn to Inside Mac: Imaging with QuickDraw which
is the definite reference on QuickDraw.
The format of a picture file is the same as that of a picture resource
with 512 added 0 bytes in front.