Hello UstadBhai:

You must search the balance between speed and size. If you set you images in desing time, then you are saving them as a resource in the same .exe file. That makes exe file too long. If you load images at run time, it supposes a waste of time, that is bigger if you images are compressed (gif or jpg), and end user can modify your images.

I recommend you to load the images when program starts. Don't use an image control for every image, because it suposses a great waste in graphics resources. Use only an image control to show the selected picture, and a image list control (Microsoft common controls) to contain all pictures. To avoid user modifications, store all your pictures in a resource file (.res).

I think that's the best way.