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Microstock Photography Forum - General => General Photography Discussion => Topic started by: pixel8 on February 20, 2015, 01:51

Title: Zipping a Photo Problem
Post by: pixel8 on February 20, 2015, 01:51

I need to zip some jpg photos so I tried win zip and also the compress info on my Mac feature to zip a 5mb file but when I checked the zip size on both Win Zip and the Mac zip they still said 5mb. Am I doing something wrong or do jpg files not zip further down than 5 mb?

Thanks

Title: Re: Zipping a Photo Problem
Post by: Semmick Photo on February 20, 2015, 02:17

JPG is a compressed file format, all data in the file is already compressed, so you wont gain much by zipping it. The only advantage is that you can bundle a set of photos, maybe add a licence etc, and then send it in one package. Zipping is file has more effect when its an uncompressed file, for example an Excel workbook. You can compress those by 80-90%

Title: Re: Zipping a Photo Problem
Post by: skyfish on February 20, 2015, 02:57

Hi. Here is better to know for what you want to zip?
1. If to decrease size of whole set for e-mail? Then see what you need -
to keep dimentions and decrease size - just resave with more compression. After 75% loss of quality will be visible
2. If to keep the quality - then resize every file
Use zip utility only for packaging

Title: Re: Zipping a Photo Problem
Post by: Difydave on February 20, 2015, 08:56

Interesting to note that in some cases, where the file (s) to be compressed are already compressed, then the resulting zip file can actually be slightly larger than the sum of the original(s)