PDA

View Full Version : URGENT Help needed with compressing pictures



Stinger123
May 14, 2007, 01:45 PM
Hello

I need to send an email with 4 pictures (I don't have .mac) so I'll use me yahoo mail. The pictures are about 12MB so I need to compress them.

I put them on my desktop
Select them all, right click, and choose "Compress arcive" (it doesn't say exactly that since my machine isn't set to english)

It then creates a single file calles "new arcive.zip" (it looks right) but the problem is that the size does NOT change. The size of the zip arcive is STILL 12Mb and I can't mail it.

Help please

thanks


epochblue
May 14, 2007, 01:47 PM
The problem with the zip style of compression is that the algorithm it uses doesn't compress things like pictures or music well. It really works best on text files and the like.

I'd recommend taking that zip file and uploading it somewhere like http://www.senduit.com/ and sending the resulting URL it gives you to the person instead.

senduit has a 100MB limit.
Stinger123
May 14, 2007, 01:51 PM
Oh - so the zip program can't zip pictures? That's good to know. Thanks a lot.
CanadaRAM
May 14, 2007, 02:06 PM
Oh - so the zip program can't zip pictures? That's good to know. Thanks a lot.

It can, but the nature of the data file is that it may not result in any savings. What format are the pictures in originally?
AlexisV
May 15, 2007, 09:26 AM
I've just tried zipping a 74Mb TIF image and it exactly halved in size. You should see at least some compression with your zipping.

To do things properly though, you need to resave your images as JPEGs. They just reduce to no more than 3Mb each, less if you're happy to keep them to screen resolution (72dpi).
epochblue
May 15, 2007, 02:46 PM
I've just tried zipping a 74Mb TIF image and it exactly halved in size. You should see at least some compression with your zipping.

To do things properly though, you need to resave your images as JPEGs. They just reduce to no more than 3Mb each, less if you're happy to keep them to screen resolution (72dpi).

JPEG is a compressed image format. TIF is lossless and has much more meta-type data that can be compressed. When you zip a TIF, you're compressing something that hasn't really been very compressed yet. Zipping a JPEG is trying to compress something that's already compressed, you're going to get much less out of it.