Blurry Images in Preview and Published

Thanks so much Kelley. 

I just got around to trying it but unfortunately it didn't fix the problem. I use screen size 4:3 (rather than 16:9) but I applied the same principles, increasing the story size to 2047 x 1535. Unfortunately the image is still blurry when imported into Rise and then viewed in Chrome at less than 100%. 

Does anyone have any further suggestions? This is definitely a bug that entered Storyline in one of the updates last year as the activities that were published prior to that date do not have this problem (but when you re-publish the exact same files, they do!)

Thank you in advance and stay well everyone :)