Can someone explain, in more depth, what shaders are, what do they do, what their uses are, and other stuff? I looked at some of the screenshots in the shader index and some of it appears to be a regular skin image. It seems just like a model with a complex skin arrangement which makes more more confused on what shaders are. Is that what a shader is? A skin image? Some of you can make extremely high-quality art work, there's no apparent need for shaders if shaders aren't just a skin image. Also, what is an HLSL shader? What does my graphics card support (I have Radeon 9600 XT)? I'm very confused about shaders and what they are, what they do, what they're for, etc..

Edit: also, what are vertex and pixel shaders? What's the pros and cons between the 2?