How to Use the Photoshop Save for Web Tool

Set Up the Comparison

In the top left corner of the Save for Web window are a series of tabs labeled Original, Optimized, 2-Up and 4-Up. By clicking these tabs, you can switch between a view of your original photo, your optimized photo (with the Save for Web settings applied to it), or a comparison of 2 or 4 versions of your photo. Choose “2-Up” to compare the original photo with the optimized one. You will now see side-by-side copies of your photo.