Images are basic part in making any website more lively and are important aspect of any website.But you need image optimization/compression for better performace of your webpage so that it loads faster.If you have large size images on your page then its going to take much time to load your page and user will definetly lose interest in such pages.

Most images on web are in JPEG or GIF format.Using any of these formats comes with its advantages and disadvantages.So there is a need to understand difference between these formats.

Joint Photographic Experts Group (JPEG) or JPG - It is a result of lossy compression technique as it reduces the size image by discarding details which are hard to notice by human eye.JPEG supports 16 million colors and therefore are better for images such as digital photographs and sceneries.But this format is not good for drawings (Drawings with straight
line and block diagrams),Clip arts and text based images.The level of compression determines the end file size.JPEG allows you to vary the degree of lossiness. If you want a very small file size, but can put up with a slightly poor quality image, you can set parameters accordingly

Graphics Interchange Format (GIF)-This another format of compressed image is saved using lossless compression technique, which means that you can restore an exact copy of the original.As GIF format supports only 256 colors so it doesn't go well with Photos and sceneries.But its good for drawings,Logos and text based images.Thumbnails and clip art can be created usingusing GIFs.