Its quite easy to resize the normal images. I mean there are many ways for doing it. But resizing animated images is quite different thing. To resize animated images we need to resize its each and every frames. So it may be hard for normal users like us.
But there is a easy way of resizing animated images(.gif formats). We can resize these kind of images using 'GIF Resizer' Software. Its freely available on Internet. Just search the name in Google and I am sure you will get it quite easily.
In software, we just need to adjust size of output image as per our requirement. And that's it. It will resize all frames automatically and give you animated image as per your requirement. I am uploading its image below so you can have some idea :