Kinda stumped. Another superadmin has same issue so we’ve opened a ticket. The upload UI just spins, sometimes times out with an “upload failed” caption after navigating to the image to upload and double clicking. Makes no difference whether using various buttons like “Select Image” (then “Drop and image her or browse”) or “Upload image” while in in Course Mgt > Properties…
Using Chrome, yes I cleared browsing history and cache…