Compression Info (Formerly: Tips on Keeping Your Entry under 75kb in size.)

[mathuwm]

a free image re sizer for Microsoft xp

direct link:
http://download.microsoft.com/downlo...ertoySetup.exe


page it is found on is at:

http://www.microsoft.com/windowsxp/d...powertoys.mspx

[Midgardsormr]

Once the May challenge is done, I think we should move this thread into the Software Discussion forum. There are already lots of good tips and utilities that it would be handy to have there. Or maybe it should just be appended to the end of the Image Export Formats thread.

[ravells]

Some good advice from RobA:

The trick here is that jpg compression is designed for photos (or photorealistic images).

It is horrible for diagrams. You would probably get a better reproduction with a 2 bit gif on the diagram you posted.

-Rob A.

[ravells]

Good article on minimising jpeg file sizes here.

Good article on minimising png file sizes here.

I've also just discovered that .jpg and .jpeg are the same (someone please correct me if I'm wrong!)

[Midgardsormr]

You are correct. The shorter .jpg extension was made necessary because MS-DOS and early editions of Windows had a three-character limit on extensions. .tif and .tiff are also interchangeable for the same reason.

Since small file sizes in PNG depend on the number of colors used, those using that form of compression may want to review the color scheme generators linked here: http://www.cartographersguild.com/showthread.php?t=567

Reducing your image to a few colors can greatly improve compressibility, but it makes choosing the right colors more important. Those of us who are stronger technicians than artists can use some help with that.

[Redrobes]

Good article on minimising jpeg file sizes here.

Good article on minimising png file sizes here.

I've also just discovered that .jpg and .jpeg are the same (someone please correct me if I'm wrong!)

Nice links except that as I read the first line it was wrong ! A JPEG is usually 24 bit but you can also do a greyscale JPG too. Thats a single channel version. That would sound like it would be 1/3 size but usually its nowhere near as small as that but it is smaller than a color one by maybe 20%.

[Gamerprinter]

JPEG stands for Joint Photographic Experts Group - a sort of unofficial consortium when JPG was being developed. Since DOS based file suffixes have only 3 letters, thus JPG instead of JPEG.

[meleeguy]

In in PhotoShop 7, I've found "Save for Web..." (to jpg) gives much better sizes than "Save as..." (to jpg). I'm sure there is a trade off but they look the same on my uncalibrated lcd monitor.