The .VGA files are sprites used to display animations. Some VGA files have a one-to-one relationship between sprite frames and animation frames while others have a single animation frame split into two sprite frames.
For animation frames that are stored in separate halves, the order of the frames can vary depending on the specific file. Some frames are stored interlaced (Left,Right,Left,Right), but others are not (Left,Left,Right,Right). Still other files may only store the left part of the animation frame while another file stores the right.
Animation frames can be 320x200 pixels (frames split in half) or 216x132 (frames not split).