This looks to be related to an issue I saw logged in the Beta version (Feature Request: Import assets and symbols on copy & paste from one project to another), but we’re seeing this in Mockups 3.1.2.
If I want to take a mockup from Project1 and move it to Project2, I can copy and paste all of the contents from one into the other. However, if one of the assets is an image, the pasted elements contain the image in a much degraded state. Now as I’m flipping through “slides” of Project2, this newly copied/pasted slide really stands out as a different quality for the part that was the image.
If there is a better way than copying and pasting elements (like drag/drop from one project to another, but that appears to shrink images too), let me know! Or, if there is a workaround alternative to finding the original image/asset and reimporting it, that would be great too.