Background colors invert when resizing?

I just finished coding my first window that loads a bitmap for it's background. neat huh? Anyway, when I fire up my program, sometimes the colors are right and other times they look inverted or something. My bitmap is a purple/black clouds thing. Sometimes, it's the original color and sometimes it's a green/black bitmap. And when it is the correct color and I maximize the window, the color changes. Any suggestions??

What are the functions you are using?

I assume you are using StretchBlt. Are you using

SetDIBits(hdc,hBMP,0, iImageY,cImageBuffer,pbiImage,DIB_RGB_COLORS);

and

SetStretchBltMode(hdc,HALFTONE);

Try to only use int multi's of the original image size for best results.

I still had problems with StretchBlt() in release but not debug. (White (255) was drawn as black (0) and the other shades had one added to them)

I think it was that the pallette was failing to align the brush but could not fix the problem with the API functions. I use another drawing lib and this solved the problem.