Animated GIFs are animated images often used on the internet.
Animated GIFs have some advantages:
They are simple to make using an animation program and a series of images, If you have a series of images such as frames from a film you can easily make a GIF.
They do not require your web browser to have a plug-in, Flash animations require the user’s computer to have the necessary plug-ins installed but GIFs are treated as normal images.
They have lossless compression so that the file size can be reduced without too much distortion, When you want to reduce the file size not too much quality is lost when compressing them.
Animated GIFs have a relatively small file size, Flash files often have very large files and can slow a website down, however too many GIF on a webpage will also slow it down.
GIFs are easy to use when creating a webpage, No special coding of formatting is required when adding a GIF to a webpage as they are normal image files.
And they are supported by all web browsers, there are very few web browsers that will not support animated GIFs.
But they do have disadvantages:
They have a maximum colour depth of 256 bit, Other image and animation formats have much larger bit depths but 265 bit is normally well suited to a webpage.
They can slow a webpage down, If large numbers of them are used on a webpage it can take a very long time for them all to load.
The often have a ‘Blocky’ or ‘Pixely’ appearance, GIFs can give a blocky quality to images that are animated reducing the overall quality.
Their use of ‘Dithering’ to prevent harsh colour contrast restricts how much the file can be compressed, Dithering takes up quite a lot of file space and there fore restricts how much the can be compressed.
Too few frames in the animation results in a jerky animation, Often the frame rate on GIFs is quite low and using to few frames will result in a jumpy and jittery appearance to the animation not a smooth image.
If not done well they can make a website visually unappealing, If they are not used well or too many are used the can give the site an unproffessional look.