For images of the same dimensions, the fewer the colours, the smaller the file. JPEG files are more popular than GIF files because they can be higher quality images with more than 256 colours. Most computers can handle JPEG files. As a rule of thumb, illustrations that can be displayed well in 256 colours or less should be provided as GIF files, and illustrations like photographs that need more than 256 colours should be provided as JPEG files. Large illustrations with few colours should be provided as GIF files, since large areas of the same colour may not display well in JPEG files.
Graphics software Creating graphics for websites requires graphics software.
This can be assisted by a scanner which allows input of images into a computer. There are a range of them available.