Wednesday, January 28, 2009

Optimizing Photoshop Graphics for the Web

By David Peters

Optimization is a procedure which can take a bit of time if you are looking for perfect results or can be fairly brief for nearly perfect results. It is your choice as to which route you wish to take. Adobe Photoshop and Adobe ImageReady include tools that help optimize images for online display quality. The best bet is to use the software you are most familiar with. If you are comfortable using Photoshop then using ImageReady is really not necessary.

The easy way:

Use the Photoshop Save As command lets you save an image as a GIF, JPEG, or PNG file. Depending on the file format, you can specify image quality, background transparency or matting, color display, and downloading method. The controls for the resulting dialog boxes are fairly clear. I recommend saving this way (using a different name) and saving the next way as a means of comparing the two results. Then you'll know for sure which is most advantageous.

For greater control and precise optimization use the Save for Web (Photoshop) or Save Optimized (ImageReady) command. It's found in the File menu just below the "Save As..." item.

The resulting tool window offers a lot of options. They're all fairly self explanatory.

Click on the tab at the top of the image area to choose a display option: I recommend 2-Up so you can see both versions of the image side by side.

The annotation area below each image in the Save for Web dialog box gives you the information regarding how the file will perform online. You should see the original image filename and file size; and the optimized image optimization options, the size of the optimized file, and the estimated download time using a selected modem speed. I use the 28.8 setting to be sure.

Now change your "quality" options to the right, and test various settings.

Nothing will actually change or affect the file until you select "Save Optimized" -- so play around until you have a good visual understanding of what to expect.

You can also set scaling at this time, and Photoshop does a pretty good job of sampling your image down to the correct size. Remember: never enlarge. - 16752

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