How do I make a "scale only" preset?

I have a "pop up" effect that animates images to pop on my video. I only care about the image animating from 0 to 100 scale. 

I made a preset that uses several scaling keyframes. The image goes from 0% to 110% to 100% in scale in 2 seconds. 

Issue 1: When I apply it on another clip, the target image's positional value changes too. I don't want that to happen, I want to retain that target image's position and only to animate it's scale.

Issue 2: Sometimes the target image has to be resized when added to my video. So my image may be at 200% because that's the size it needs to be. But when I apply the preset, it will apply the actual scale values of 0-100%. Which will make the target image a lot smaller. Animation happens, but it's a lot smaller now. How can I solve this so that the target image scales up proportionally?