These are some of the tools and features that I find myself using on a regular basis when creating images for the web. These include using the slice tool on images to decrease page load times and using pre-set effects that save time when creating forms or menus for your site.
20 Things About Photoshop You Have to Know - File Browser, the Layers Panel, and Effects (Page 6 of 7 )
The file browser is like a built-in Explorer that shows only pictures. Well, mostly pictures; it also shows PDF files and zip files, but the PDF is obviously produced by Adobe and can therefore be used natively in Photoshop, and zip archives may well include pictures. It is accessed by clicking the folder and magnifying glass icon at the top-right of the screen.
The Layers Panel
Itís hard to imagine using Photoshop at all without having the Layers panel present. Located at the bottom right of the workspace by default, it is home to all of your layers and some of the layer tools. Layers can be switched on or off, making them visible or invisible respectively, or their opacity can be changed to alter their transparency. Both of these features are extremely useful when creating roll-overs or animations. Also, the layers panel is essential for adding effects to layers (see below).
Effects are very similar to styles in that they can uniformly change the appearance of your layers. The main difference between effects and styles is that effects are linked to the layer contents; when you change the layer, the effect changes with it. There is a pre-set selection of effects available to you, ranging from shadows and strokes (outlines), to gradient and pattern overlays.