Hi GrooveJedi
Extreme JPEG
The second method for saving JPEGs in Photoshop is the Save for Web command (File > Save for Web.). You may have thought that Save for Web was just a fancy version of the Save As command, but there’s a bit more to it. For starters, Save for Web does a better job of compression, even at the same relative quality setting (Save for Web uses a scale of 0-100% whereas Save As uses 0-12). For example, Figure 5a was saved with the Save As command at a quality setting of 6 (equivalent to 50%) resulting in a file size of 26K. Figure 5b was saved with Save for Web at a setting of 50% producing a file size of only 14K. There is no perceptible difference between the two images.
Save for Web also allows you to perform weighted optimizations by using an alpha channel to vary the compression amounts in an image. (It’s not as difficult as it sounds.) First, make a rough selection using the Lasso (L) or Quick Mask (Q) around the areas of your image containing important detail. The selection should not be exact (see Figure 6a). Next, save the selection to an alpha channel by selecting Select > Save Selection. The Save Selection dialog appears (Figure 6b). Choose New in the Channel box and type a name for the channel in the Name box (I called it "JPEG Mask", but it can be anything). Click OK and the selection will be saved as an alpha channel. You can remove the active selection by pressing Ctrl-D.
Now open Save for Web (File > Save for Web). Select the 2-Up view in the upper left to compare your original document in the left pane to the JPEG preview on the right. Under the Settings box in the upper right, select JPEG High and click the mask button next to the Quality box (see Figure 6c). The Modify Quality Setting dialog now appears (Figure 6d). In the Channel drop-down box, select the name of the channel mask you created previously. Under Quality, slide the white slider to 70 and the black slider to 40 and click OK. This means that the masked area will have a quality of 70% and the rest of the image will be 40%. Click Save to name your new image and save it to disk. The final image is seen in Figure 7.
Although it’s a neat trick, weighted optimization can be a lot of work for a little gain. In my tests with typical photos at 400 to 600 pixels in length, I was only able to save a few Kbytes. In some cases I managed to increase the file size over standard optimization. It seems to work best with higher quality settings and, of course, varies from image to image. Whether or not the extra effort is worth a few saved bytes is up to you.
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Ok I admit, I didn’t make this up myself 😉
Check out this link to more useful information on treating images like a lady:
http://www.naturephotographers.net/articles1002/mh1002-1.htm l Greets
Littleboy 😉
"GrooveJedi" wrote in message
Hi everybody. I was wondering if someone could help me with the following dilemma:
I am trying to downsize JPGs using Photoshop without losing too much of the integrity of the file. These files need to be small because they are for the web. Say for example I "Save for Web" and my JPG is about 40k. Are there any other methods for reducing the file size other than lowering the quality of the image? I’ve already lowered the quality of the image as much as I can afford to and the file is still about 19.5kb. I need the file to be less than 10kb but don’t want the image to get blurred further.
PLEASE HELP! 🙂
