jpg quality when archiving?

[86047]

when jpegs are archived into zip or whatever in panther and later's "archive" feature,
do they lose quality?

If they are compressed (archived) and then uncompressed (eg. by stuffit expander), is the quality the same as the original? Is it lossless compression?

Thanks just trying to free up disk space on my relatively small ibook drive (some old images)

 

[Blue Velvet]

Zipped files are lossless although I'm not sure what kind of compression gain you would get from zipping up JPGs, if any at all.

 

[dllavaneras]

I've tried to compress jpegs by zipping them but the file size is not that much smaller than the original folder...

 

[ChrisA]

when jpegs are archived into zip or whatever in panther and later's "archive" feature,
do they lose quality?

If they are compressed (archived) and then uncompressed (eg. by stuffit expander), is the quality the same as the original? Is it lossless compression?

Thanks just trying to free up disk space on my relatively small ibook drive (some old images)

You can't compress a JPG image. OK you can try but the result will be like maybe 98% or the original size. Loss-less compress is called "loss-less" becase nothing is lost during compression. So don't worry about loosing quality but it's pointless so don't bother.