GIF Prep is a free utility that solves a pervasive, but easily fixed, problem for Macintosh users creating Web graphics. The problem is the difficulty determining the true size of your GIF (and JPEG) graphics because of the dual nature of the Macintosh file system.
GIF Prep is now on version 2.0 which adds support for MacOS X
GIF Prep is nothing more than a Macintosh resource fork stripping utility, and is included in the archives for most of our Macintosh Web graphics tools. GIF Prep was originally created with very minimal effort - it is not fancy at all - to answer one of the most frequent questions we have ever been asked. Why does the Finder say my file is bigger than your software says it is?
The answer to that question is the Macintosh uses a file system that references two separate files, one called a "resource fork" and one called a "data fork", as a single file visible on your desktop.
In the "data fork" of a Macintosh file is your cross-platform GIF or JPEG file. Anything in the "resource fork" is Macintosh, application specific fluff. Depending on what method was used to create your graphic, there may be nothing in the "resource fork" or more data than is in your actual GIF or JPEG file in the "data fork" of your Macintosh file. This is especially true of files created using file format plugins, such as our PhotoGIF and ProJPEG, in Photoshop, which is why we created GIF Prep.
Once you drop a GIF or JPEG file onto GIF Prep, the resource fork is stripped, and the true file size for purposes of the Web will be reported by the Finder.
GIF Prep does not actually change the GIF or JPEG data in any way. It only makes it easier to tell how large your GIF and JPEG files are, so we get asked a still frequent question less.
Download GIF Prep now. It's free. Grab some other great Web design tools from BoxTop while you're at it.