Working with JPegs and Gifs

The JPG (or JPEG) format is used for images with lots of colours, while the GIF format is better for logos and line art that have fewer colours. JPGs and GIFs are the two most common image files found on the web, and can be opened in all web browsers.

JPGs

JPG images are better at holding more colour information when they are being saved.

This means that shading and subtle colour changes look better if you save them as JPGs.

JPGs are most commonly used for photographs as they can hold information about the thousands of different colours in a photo without making the file size too big.

To do this they use a 'lossey' form of compression. This means that some of the picture information is 'thrown away' but if it's done right this shouldn't be noticeable to the naked eye.

GIFs

GIFs are better at saving images with sharp lines as they don't throw away any of the picture information.

They are usually used with text, logos, buttons, lines, and other images that have been created on a computer.

They are not very good for photographs or pictures with delicate shading as they can't hold information about more than 256 different colours.

GIFs are also used with images that have a transparent background, and with simple animations - JPGs cannot do transparent backgrounds or animations at all.