Image Effects

This is not GLSL and it doesn’t really have to do with games either…

I was just bored recently so I thought I might make a simple light weight image effect program where developers can make their own image effects…

It is done per pixel where each effect has a method:

public Color filter(Image img, int x, int y);

But I want my own default image effects which are built into the program but every time I search on how to do an image effect I just get some Photoshop or Gimp tutorials…

Is there any website where they teach you (not show you, there is a difference) how to make certain image effects?