Layers are transparencies that allow you to modify an image without actually touching the background image. Imagine if you had a piece of paper in front of you, that would represent the backgrounds, then lets say you put a transparency on top of that (like those used in overhead projectors) that transparency would be like a new layer, you could draw on it erase things on it or just plain get rid of it and you would never touch the original image.
What can i do with layers?
There is an extremely large number of things you can do with layers, you don’t just have to put text in it or add little things to it, you can add color to black and white photos, change the opacity, and much much more
Here is an example
this is a red Dodge Viper that i used in one of my sig's
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/001.jpg)
I wanted the paint to look like a flag so here is what i did. I duplicated the background then removed everything but the viper and then turned down the saturation (I made it a greyscale image)
PSP:"shift+h"
Photoshop:"shift+ctrl+u" or "shift+u"
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/002.gif)
after that i added this flag (i had to modify it a bit by stretching it, ill explaine that later)
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/002.jpg)
I then removed the information around the flag that was not needed (only the information above the Viper remains) then turned the transparency into an "overlay"
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/001.gif)
after that this is the Viper i am left with
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/005.gif)
doesnt look right does it? we have to go back to the original image, duplicate it, then drag it up to the top, then we have to remove everything except for the things we dont want colored (i.e. the headlights the stripe and a few other things) i have the stripes in a deifferent layer than some of the other things but that is my choice and not necessary
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/003.gif)
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/004.gif)
heres how it looks when each layers is added
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/viper.gif)
and the final version at 30% of the original size
![Image](http://img.photobucket.com/albums/v256/dave0616/shop/003.jpg)