the most common graphics file formats on the Web are those with the extensions .jpg and .gif.
JPG - is short for JPEG (Joint Photographic Expert Group), which is a popular compression standard for photographs and other images.
GIF - extension stands for Graphics Interchange Format, a standard developed by CompuServe in the late 1980s. both these graphics formats are platform-independent, which means you can use them on a PC, Mac or UNIX.
PNG - (Portable Network Graphics) is a graphics format specifically designed for use on the World Wide Web. PNG enable compression of images without any loss of quality, including high-resolution images.
BMP - (bitmap) the standard graphics file format on Windows-compatible computers. Bitmap graphics support 24-bit color and can be saved for Windows or OS/2 systems.
WBMP - is a graphic format optimized for mobile computing devices. A WBMP file defined is a simple black-and-white image file with one bit per pixel and no compression.