Quad edges flickering.

Hello all,

I’m trying to figure out why the moving images in my engine flicker. Here is the link to the engine download.
The engine pads textures to the correct size if your image is not power of two. One thing that I noticed is that if there is space(transparent pixels) between the edges of the original image then the flicker is reduced (almost hard to notice). Could someone provide some inputs to what could be the reason for that? Thanks a lot for your time.