Animated files can have quite large file sizes, large files can take a while to load esspecially on websites an so there are different widely used techniques for reducing file size.
Image Quality: Reducing the quality of the animation is a simple way to reduce its size, you may find that your animation dose not need to be in full 1080p High Deffinition, for instance, and that a much lower quality will be just as good. It may be possible to compress the image in order to save space, this may also lead to a reduction in image quality. Reducing the image quality reduces the file size as it does not need to store as much information.
Frame Disposal: Frame disposal is when animation programs and files dispose of the current frame in the animation before loading the next frame. This is quite an effective method of reducing file sizes. A few methods exist for frame disposal but one of the most common is frame transparency this is where the frame quickly fades away behind the next frame, this disposes of the frame but at the same time gives a smooth flow between frames.
Auto Crop: Often animation and normal images have allot of wasted space around the main image, this still uses up file space and therfore increase the file size. Auto crop is a feature of most animation programs, it finds unused space and physically reduce the size of the image by removing it. Reducing the size of the frame again reduces the ammount data that is stored.