Im having trouble with the white outline around my gif animations

[Sedit]

I think its something with transparency but I cannot get rid of those white outlines on my gif animations. I tried using the select tool then expanding it a pixel and deleting the semi transparent white around the edges. This worked but to make it so deleting the transparency was easier I brought the image in as a gif image then I added a animation to it. The white was mostly gone but now the animation i brought into the gif has turned black and white.