By Pete Cooper

Download times can mean everything on the Web, especially since the majority of your Web site visitors will be using 56k dialup modems. The smaller the file sizes of your images, the quicker they will load, and the happier your visitors will be. Another benefit is that your site will be using less bandwidth, which may save you hefty traffic charges later on. But how can you reduce the file sizes of your finely crafted images without losing quality?

A couple of years ago, you would have had to tweak with the settings in Adobe PhotoShop, or buy a software package dedicated to the job. Thankfully, you can now find a simple, and free, solution from Adobe on the Web. Adobe creates a plethora of graphics and publishing applications, but it also offers some free little-known 'Web Services' straight from its Web site. One of these is the Adobe Image Optimizer.

How it Works

The optimizer is extremely easy to use. The introduction screen tells you exactly what to do, and presents you with a box in which to enter the filename of the image you want to be optimized. You can also click the 'Browse' button and simply choose a file using the standard Windows dialog box.

The optimizer will optimize images in 11 major formats, many you probably don't even use. The supported formats we are interested in are GIF, JPEG and PSD (native PhotoShop files). The optimizer will optimize files up to many megabytes in size, so you don't need to worry about the size of the initial file. It can even handle transparency effects in your PSD files, and it will generate a transparent GIF, if you choose GIF as your formatting option.

Selecting a Method of Compression

Once you have selected your file, you can choose which style of optimization you wish to take place. You can select from several different options, I have highlighted the most useful ones here:

JPEG High to Low quality : This will compress your image at a variety of levels. The more compressed your image is, the lower the file size will be, however you will have to make a trade off between file size and the quality of your image. Using this option allows you to see the effect of a range of compression levels, allowing you to choose which you find best.

GIF High Quality + GIF Low Quality : This option will allow you to retain the crispness of the original image, and will merely reduce the number of colors within the image to reduce the file size. The high quality option reduces the colors to a lesser extent, and the low quality option reduces them as far as possible.

Colors which are dropped can be reconstructed using a technique known as 'dithering'. This is where two colors are placed closely together to create the effect of a color which is in-between. This technique can often work well, but may cause a patchy or speckled effect on graphics which contain many colors. These options are best suited to diagrams, charts or graphics which contain large areas of bold color.

GIF vs JPEG : This option allows you to see a comparison between the two methods listed above (JPEG and GIF). This is an ideal choice if you're not sure which you should choose. When complete, you will be able to see both methods side by side, as well as the file sizes, so you can make an informed choice. You could then re-optimize using the specific method, to get better results.

There are also a few other options such as 'GIF - Web Palette' which puts your image into the 216 optimized Web colors, although the usefulness of this is declining rapidly as 16-bit color graphics are becoming the standard.

Optimize Away!

Once you have selected your file and your compression technique, you're ready to go. Once you've clicked on the 'Optimize Your Image' button, your file is sent directly to Adobe's Web server. Do remember that you will need to wait while the file is uploaded, and this takes a variable amount of time depending on the speed of your connection and the size of the file you're sending. If you're sending a multi-layer PSD file, expect to wait a little while.

Once your file is uploaded, you will either be presented with the results of optimization, which load gradually, or a simple error message informing you that your file is corrupt or unable to be optimized. If this happens, the best thing to do is check that the file isn't corrupt by opening it in your graphics package and then try again.

Once the results page has appeared and the optimized graphics have finally loaded, you can visually compare the graphics and also examine the new file sizes. Saving your selected optimized file is easy. You just right click on the graphic of choice and immediately save it to your hard disk or, if you're using a Mac, hold your mouse button down on the graphic and select the Save command when the menu appears.

In Conclusion

The service is very fast and reliable, but, of course, every service has its disadvantages. You can't select different areas of the image to be compressed at varying levels - which improves the quality of the image - as you can with today's sophisticated software packages. Sometimes it can also refuse to optimize an image which isn't corrupt and doesn't appear to have any inherent faults, but these rare glitches are a small price to pay. Often, resaving the image from the original package will overcome this problem.

However, the Adobe Web Service is totally free, and does what it says without major fault. The good thing about this service, over its main rivals, is that you don't have to sign-up for anything. You don't need a username or password, and you can use the service as-is immediately. We definitely recommend this service for its ease-of-use, and the simplicity with which you can get started using it.