The Layers Palette is a powerful tool and is one of the palettes that I keep open all the time. You can call up the Layers Palette if it is closed or hidden by going to Window in the menu bar, and then asking it to show layers, or put a check by it depending on what version of Photoshop you're using. Layers allow you to alter different images all in one file, so that you can combine them and yet still have the ability to go back and change things as if they were separate. Long ago all image editing programs were flat... if you opened an image of a person, and placed them onto a background, once you placed them there, and deselected them, they became part of the background, and the part of the image that was behind the person was lost. With layers you can now place the an image on top of another, and you can always go back and move or resize it.

With the Layers Palette now up, you can see that there is a thumbnail of the image you have open, the layers title is probably "Background" and it's also locked most likely. You can double click any layer and rename it (in Photoshop 6 you will have to right click on the layers name to do it though). To the right of each layer there is an eye, which shows what layers are currently visible. To the right of the eye is a paintbrush icon, which shows your working layer, which will also be highlighted. If you click the boxes in the column with the paintbrush icon you will notice a chain appear in them. You can only work in one layer at a time, but clicking these boxes will link these layers to your working layer. When you have layers linked, you can use the move tool on one layer, and all the layers linked to it will move and stay in place.

Below the word Layers on the tab is the Blending mode, layer 0 happens to be set at Screen mode. I find the blending mode to often be the easiest method of getting images to mesh together, but more than setting the Opacity down. If you pull out the blending mode you will see that there are many different blending modes. You should try blending images with all of them to see just what they do. I use Screen, Multiply and Luminosity often, but no one mode is always right. Opacity deals with how opaque your image is, set it to 50%, and you will see that your top image is now half transparent. The Fill setting does an identical effect to the Opacity, only if you have created a layer effect like a glow or shadow to a layer, using Opacity will cause the entire layer to fade out, where as the fill will only fade out the layer's image, but not the effects you've placed on it.

Under the blending mode box there are four options to lock your layers, from left to right you can lock any transparent pixils, lock visible pixils, lock from moving any pixils (but you can still paint on them and do other things), and then lock, so you cannot edit that layer at all.

Along the bottom of the Layers Palette are six icons... the first allows you to place ad a layer style like a bevel, shadow or glow. You can also do this from the Layers menu, but this makes it more handy. To the right is the mask icon. If you click it you will notice that there are two thumbnails for the layer you were on, the first will be the image, and the second will be blank. Take the paintbrush and paint on the layer... You will notice that everywhere you paint the image vanished. This is because everywhere you've painted, you've masked off the image from view... it's still there, and you can right click on the layer and turn off the mask. This feature allows you to visually delete a part of an image, without really erasing it. Next to the mask icon is the new set folder. Clicking that will place a Set folder into your layers. This can aid in grouping layers if you have many, and it allows you to easily group layers together. To the right of that is the adjustments. I don't often use this icon, you can adjust aspects of the layer like the brightness/contrast and other things, this is also under the menu bar under Image/Adjustments, and there are more options there. The final two icons are the new layer, which creates a new layer, and the delete layer. Anytime you click the text tool in your image, it will automatically create a new layer for it, and it will do the same any time you use the paste command.

Finally, directly under the close box for the palette is an arrow that points to the right, if you pull it out you will find commands for the palette's options, like how large the thumbnails should be, and also different methods of flattening your image, it must be flattened to save as a .jpg format, though you can now save a layered file as a flattened one, by using the new "Save for web" command under File.