Square GIF resize puzzle?

Question

gif

Let's start with the fact that Wordpress does not properly resize gifs and they stop working (animated) in reduced sizes. I installed the Animated Gif Resize plugin, which supposedly solves this problem. And everything was fine until I started uploading square gif animations. If the full-size ones work ok ( bit.ly/1XzYFM4), then the reduced ones show an interesting effect on the right and bottom edges -

Has anyone met this before? I will be grateful for hints.