Premiere Vignette

alright im trying to create an artificial faded vignette in Premiere Pro.

so far i've just been working on ones in photoshop then trying to import, but when i save as a .gif the fade never exports and it just ends up being a solid line.

or if the fade does work the transparency in the middle where the video is is white.

am i missing something?

or does anyone know of any other ways to do it?

thanks