What is a good program that will parse information from a JPEG or any other picture format that stores information with it?

do you mean metadata?
I think any programs like quickshow or kpaint can show the metadata information.

If you mean metadata, like rch says, then most paint and webpage design programs will work. On the other hand, if you mean steganography (hiding information in pictures), then a search of google (steganography +linux) will give you all sorts of toys to play with.

Oh, BTW, as far as the steg programs are concerned, using them to do "really bad things" is not the best idea. They are good as an example of ways to hide information in other information, but for anything you don't want to end up in prison for, they're like sending out a beacon saying you're a bad guy.

I have an aquaintence that gets almost weekly scans by .gov-related addresses because her site is a picture-based site. For most law-abiding (or should that be mostly law abiding?) citizens, steg work is something interesting, but I thought I'd mention that it isn't exactly uncrackable. After all, steg's appeal is that it's hidden in plain sight.

steghide is a nice tool.

I don't think you are right. Steganography MUST be used in conjunction with strong encryption and not alone.
For example steghide compress and encrypt the data using AES (by default) and only then it embeds the info into the cover file.

What is your opinion?

Maybe you are thinking of identify which is part of the ImageMagick set.
For example: identify -verbose logo.gif
More commands with identify -help