Introduction to web graphics formats

GIF (Graphic Interchange Format): When images are save in gif format, a colour palette is created for the image summarizing all the colors contained in this image. The maxium number of colors for a gif image color palette is 256. Gif file is usually very small due to it's small maximum number of colors permitted. It is very suitable for graphics containing solid color areas such as logo,
line art, banner... Gif file is not suitable for graphics
containing smooth color tones and gradients, such as photos, color paintings...

JPEG, JPG, JPE (Joint Photographic Expert Group): JPEG compresses images by converting them into frequency spectrum through inverse cousin transform and then removing those frequencies human eyes are not sensitive to. It is very suitable for photo and painting images, which contains smooth color tones or
gradients.

PNG (Portable Network Graphics): PNG is an open standard created after the American Company Unisys claimed the patent for the LZW compression algorithm used to GIF images and demanded license fee for using GIF formats. PNG supports both graphics containing solid color areas

and graphics containing smooth color tones.