It sounds like you are positioning or resizing your character while you are not at Frame 1 on the Timeline. For example, if your load your character at Frame 1 but then move to Frame 100 and reposition your character, the result will be that the character transitions from Point A at Frame 1 to Point B at Frame 100. This is because Transform keyframes are set every time you move your character.
So to resolve the problem, just make sure you do all your positioning, resizing etc. at Frame 1. Then you can start animating your character as you wish.