Often files are hidden in
.jpg files simply by opening them up with 7zip, then closing them again. Mac OS X archive utility does not have this ability. Is there any software available for osx that does?
Actually all you need to do is change the file extension from .JPG or .JPEG to .zip. If it is indeed a zip file the O/S' unzip program should unzip it.
Failing that I use The Unarchiver
As a replacement for O/S X's built-in zip compression utility as it handles more formats.