What happens if you map a texture bigger than your polygon onto the ploygon?

I sould see for myself but i haven’t figured out how to take a .bmp and make it be a texture

Eh?. You mean like you have a texture of the size 256*256 and say a quad like so:

-5,5,0
-5,-5,0
5,-5,0
5,5,0

Well, depending on how far or close the quad is either minification or magnification occurs. If far away texels will dissapear and if the quad is close texels will become bigger than the screens pixels.

Or do you mean how to assign texture coordinates?

Ok, I know what you mean. Thanks. What happens if you map a square image onto a triangle??? Does it clip the image?

You can ofcourse only specify 3 texture coordinates for the triangle. Think of
the triangle like a cookie cutter and the image like the cookie dough…

So it will clip.