How can I extract the matrix of pixels from an image?

I've seen a lot the fact that:

The image is divided into a matrix or array of small picture elements, or pixels. Each pixel is represented by a numerical value.

I need the matrix of pixels in order to be able to apply haar wavelet transform for several purposes like image compression, image recognition, etc.. Can anybody tell me how to be able to extract that matrix of pixels from an image? is there a way of reading each value? What type of images does it support (jpg, gif, png, bmp) ?

Well, I know the Bitmap class has, for example, a GetPixel() method that returns the image color in the specified position. That is one step for image recognition. It has other methods that you should look into and see if you can use it for your purposes.

Maybe this thread will help you out. :)
http://www.xtremevbtalk.com/showthread.php?t=128875

Thanx for your suggestions, I'm researching the bitmap class, also I downloaded the triangle.zip, I'm going to look at it. I'll tell ya if I found what I needed. Thanx for your help. :)

Sorry I got disconnected from this, I saw triangle and couldn't still find what I'm looking for.

What I'm trying to do is to do a haar wavelet trasnform of an image, in order to do that I need to extract the matrix of coefficients of pixels in order to be able to process the wavelet transform, which involves average and differencing.

See the following images which tells what I am trying to do.

If somebody have done this in dot net or at least have an idea how can I get that matrix of coefficients, I will be grateful. Thanx in advance.