The low-resolution driver, MCGA256.DRV, uses a 320-by-200 display format with a 256-color palette. Low-resolution images require one-fourth the amount of memory and disc space of a 256-color high-resolution image. As a result, data transfer of a low-resolution image is faster than that of a high-resolution image. Also, because the entire display memory fits in 64K, the driver is simpler and faster.
Displaying high-resolution images using the low-resolution driver has the appearance of zooming in on the image. The aspect ratio also changes when displaying high-resolution images with the low-resolution driver. To use images created for a high-resolution display, you might crop the image or scale the image appropriately.
Another way to display 256-color images on standard VGA displays is to use DisplayDib. This function uses a 320-by-200 or 320-by-240 full-screen display format to display images with a 256-color palette. Use this function when you need to switch between a high-resolution display and a 256-color display to effectively show your images. The DisplayDib function is described later in this chapter.