I think what you have is a jpeg pic file embedded in your .elm email. I highlight the pic, just like you would text and then copy it, then I create a new file in photoshop (one cool thing in photoshop is when you create a new file and you already have somthing copied to your clipboard, photoshop makes the new file the same size as the clipboard pic). Then all I have to do is paste the pic in the newly opened photoshop file. From there I can resize the pic if needed. Then I just save it as a jpeg file.
Ifranview might have some of that capablility, I'm not sure ...but it sounds like you found an even simplier way to handle it. I had never heard of doing it that way.