You may have seen Web pages with wraparound graphical interfaces and wondered how they did it. One large GIF image with a transparent area for the page content could take forever to download and display. The larger the image, the more likely that it will be caught up in an Internet traffic jam; smaller files have a much easier time negotiating the Internet maze. The same problem can afflict large images used for image maps. The solution is to slice the image into smaller files and then reassemble the sliced images using a table. Button or area links can then be created using image links or image map hotspots. Not only do the smaller image files have an easier time making it to their destination, they also begin arriving much earlier, giving the user an indication of what the image will be. Another benefit of creating a sliced image for a wraparound graphical interface or an image map front-end is that the different sliced images can be individually optimized, which can further reduce the number of bytes consumed by the sliced images.
There are a number of free or inexpensive image slicing utilities available on the Web that you can download and try:
ShoeString's PictureDicer at www.ziplink.net/~shoestring/dicer01.htm (Windows/free).
Bisector at www.rubyarts.org/~sbrekelm/bisector/ (Windows/free). Works with Photoshop PSD files, which are then output as BMP files. You can then convert the BMP files to GIF, JPEG, or PNG files in your image editor.
CoffeeCup Free Viewer Plus at www.coffeecup.com/viewer/ (Windows/free). An image viewer that also slices images.
Ulead SmartSaver Pro at www.ulead.com/ssp/runme.htm (Windows/$59.95). A general-purpose image optimizer that also does image slicing.
A number of image editors also include image slicing utilities or wizards, including Paint Shop Pro (www.jasc.com/), PhotoImpact (www.ulead.com/), Adobe Photoshop (www.adobe.com/), and Macromedia Fireworks (www.macromedia.com/).