alternatives to Magiciso?

I'm looking for something that will allow me to package disk image files such as .iso, .img, or, .nrg that have aggregate size more than 300 Mb, but usually in the neighborhood of 700 Mb. however, my search has yielded no results except magiciso 5.5, which can only handle 300 Mb at one time without buying it.

my current software allows me to package .iso's, but only from disk media. I want to see if other, possibly free, solutions to this problem, which I have been unable to find and probably wont. Help?