[WP Smush Pro] Existing images not being downsized + can't choose directory

Hi, two questions here really, but the first is most important atm:
1. I've updated the settings on smush pro to disallow images larger than 1920x1920. I assumed that when I applied that it would update images that had already been uploaded, but it does not seem to be the case. Is there any way to force Smush to resize those larger images (some are up to 3000px or so, uploaded by user)?

2. When I click on 'Choose Directory' it just shows the loading gif and then nothing happens. I'm on multi-site, so maybe this is related to that?

Appreciate the assist. Thanks!