Hi Brenda, I came across something by accident that may help.
If you import the characters or any jpg image/illustration and then crop them in Articulate, a pixel or few should do it, the images render infocus. Not sure what is going on behind the scenes in Articulate but looks like it sharpens or saves them in a different image format when cropped in Articulate. You can also resize them larger and they are still in focus, albeit a tad soft and grainy.
Here is a test file I did on 100x100 slide, on the left are straight imports and how they render ) , on the right are the (in Articulate) cropped versions of same imports, and larger renderings on 2nd and 3rd slides.
https://360.articulate.com/review/content/85d33bb7-6d77-4634-bc94-e38aaf739279/reviewImage formats:
https://designshack.net/articles/graphics/svg-vs-png-vs-jpg/