Viruses, that effect combines particles with some image filters... by the looks of it, you seems pretty new to all of this. I think you should begin with easier things, like simple frame-based animations.
About your pixel doubts, a pixel is a point in an image. It is identified as two coordinates: X and Y. The 10, 10 pixel, as you've said, is the point located on the 10th column and 10th line of the image.
By the way, importing game content from external editors into your game (such as animations) should be handled by yourself, unless you use someone's engine instead of making one.