☛ - It is always a second block in GIF file.

☛ - An area of pixels usually referred as screen, is defined by LSD.

☛ - GIF file size is defined by this area.

☛ - When the logical screen is larger than the image, some space is displayed around the image.

☛ - As per the size of the images, the logical screen size need to be set based on the width and height of the images.