Does anybody know of any software which will allow me to compress an ISO. file?


If you are just aiming to compress it for moving, then 7-Zip or another decent file compressor is what you're aiming for, just don't expect them to do too much as often the contents of ISOs are already compressed (plus it can take a REALLY long time to try and compress huge ISOs for little to no gain)

For playing around with it and keeping it as an ISO, I'd suggest checking out MagicISO as it has an "ISO Compression/Decompression" system in the newer versions (see here) that may help you out.

  • 3
    ISOs may or may contain compressed data, but the format itself is not compressed. – emgee Jan 26 '10 at 23:08
  • Remember, some compression containers (like windows built-in zip) have limitations on file size. Make sure your compressed files decompress OK if they are over the 2GB or 4GB magical barriers. – Goyuix Jan 27 '10 at 3:57
  • I would add that PowerISO also support a compressible image format (.daa) which you can load as a virtual drive letter (a feature of poweriso). – mtone Jan 27 '10 at 4:20

Any compression software will compress an iso file.






However, I suspect you want something more... like compress the iso file bust have it still be an iso compatible image?

For that, I don't that that is doable.

  • to make an iso of compressed data, first compress the data, then make the iso. any of the compression tools you mention can compress the data. – quack quixote Jan 26 '10 at 22:07

I think what would be blank space (and thus zeroing would be a win) on a HD image, but I bet a CD has none, and probably just automatically files the empty space at the end of files with 0 anyways.

So no, 7zip is probably your best bet if you want to save space.


MagicISO supports Universal Image Format (UIF) which supports compression and encryption. Although compressed, the image is still mountable.


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