2 Replies
Phil Mayor

This may help, graphic your screenshot at a high resolution, insert onto your slide but keep it at its real size ( you may need to right click and resize to its real size as images are resized to fit the slide)but off slide, copy and paste this onto you slide and resize to the size.  Do not delete the off slide copy. When you zoom now it should be better.

this is because the library in storyline optimise images to the size in project by keeping a large image off slide it does not optimise the image.