While I am unfamiliar with and do not use ISO images, I do know some information is
available through a search; of the results, a few examples should be forthcoming; per:
' Mac OS X edit ISO images ' - google results page URL:
http://www.google.com/#hl=en&source=hp&q=MacOS+X+edit+ISO+image&btnG=Google+Search&aq=f&aqi=&oq=Mac+OS+X+edit+ISOimage&fp=d9ca629f83f82f8a
Appears ISO images are also common with PCs or perhaps Intel-based Macs,
with BootCamp; if related to newer hardware & OS X... This obviously would
exceed an older PPC computer's capacity unless it was running some Windows
emulation software, or related image files. Where did you get this image file?
There is a possible match in the first pages of the search result link, above.
In some case, you can't edit these; according to several items I've read the
process may be conditional depending on the file's purpose & the OS.
What is the ISO image related to? If it was created by a specific
software or OS, then editing these may require suitable tools.
Good luck & happy computing! 🙂