What is the difference between JPEG , GIF and PNG?

HP has done a very nice job of putting together the differences between them.

JPEG: a JPEG is a digital image file format designed for maximum image compression. It is the best way to format your colourful photos. Also known as .jiff, .jpg, .JPG, or .JPE

GIF; Lossless compression technique. it is more widely supported by Web browsers than the JPEG format. It is well suited for compressing areas of images with large areas of the same colour – such as computer-generated art and line drawings. It is also a good option for putting animation online. Images are compressed in to a 256-color or 8 bit image.

PNG: Lossless compression technique. Like GIF but does not support animation.

When to choose what?

As evident from the description above, since PNG is a lossless compression technique the images will be of high quality but of relatively larger size than jpg. Choose PNG where quality is of utmost importance. Choose jpg when you won’t mind the slight reduction in quality but you want to save your bandwidth since the images become really small.

How to create your own GIF animated pics:

There are a host of free online services available to do this. One of them is GIF Ninja. You simply need to provide the site with 5 images and it will rotate those images for the duration specified by you in the “Choose the animation speed for your gif” box, thus creating your own animated gif image.

When to choose jpn, png or gif and differences between them? – Image format chooser guide is a post from ReviewOfWeb