Image resizing using code (.jpg and .bmp)

I want to resize images using code. You know like PSP does when you resize a picture. This is for creating thumbnails.

You can use StretchBlt from the API. if you don't know how to include API calls have a look at my demo projects you can find at

http://derzirkel.tsx.org

or if TSX doesn't work:

http://members.xoom.com/Der_Zirkel/