Drag and Drop alignment

I've got a drag and drop quiz slide, where learners drag images onto drop targets. I've got the interaction set to reveal the drag items one at a time.

When I'm editing the slide, the images are all nicely aligned in the center, but when I play the interaction, the alignment is all not perfect. Some images are off-center when they appear. Its not sticking to the dropped target

Any ideas how to fix it?