Optimize your image to decrease download time
Once your image is ready to be saved, go to File>>Image Preview (Figure 25). This is where you will get your photo ready to be posted on a Web site. Because computer screen resolution is so low (compared to print), you can actually reduce the size of your file—decreasing page download time—by decreasing the quality of your picture.
If you strike the right balance between file size and picture quality, you shouldn’t be able to notice the quality degradation in the picture.
How to optimize your image
First, make sure the “Format:” box says “JPEG”.
Use the arrow next to the number box by “Quality” to adjust the picture. Experiment, pulling the quality to below 50% to see the effect this has on your picture.
Now, pull the quality up until the lowest quality at which you don’t notice a significant change in the picture. This will generally be above 60, and more often, between 70 and 80.
Look at the file size, just above the picture, where in the image above it says 157.70K. Aim to get the majority of your images under 30K, and if you have many images on one page, make the file sizes much lower than that (like 10K per picture if you have 3 images on the page).