File>Save for Web and Other Devices
Gif - Graphics Interchange - Format. Maximum of 256 colors. Image quality is not sacrificed as file size reduces however images with many colors will lose compression and therefore lose quality.
jpeg - allows a selectable tradeoff between storage size and image quality
png-8 - comprises a max. of 256 colours, like GIFs (THIS IS VERY LOW QUALITY if it is more than just a few colors)
png-24 - can contain up to 16 million colours - file is larger than png8.
wbmp - (Wireless BitMap, a graphic format optimized for mobile devices.)
Choose Save and the location for your document