Hi and welcome The_Deaner_Breakdown,
1.0.2 is pretty old and a lot of things have been reworked/improved since.
Dev build are a lot faster and visually better (under Windows), you should try it (download.tuxfamily.org/morevna/packages/synfig/)
About your PNG’s, beware the way you import them: they should only use relative path to the project, it is a common issue.
Enjoy !