I just talked with the Shopify help chat, here’s what they said:
Hi! This is a current issue that our developers are aware of and working on. Things like this don't typically take too long to fix, but I don't have an exact estimate of when it will be back up and running. I can personally send you an update once things are back up and running
so it should be fixed soon, and isn’t on our end.
Edit for workaround:
As a temporary work around, you can add the images to your files (Settings>Files), and then in the product editor, click the Add Image from URL button and add the URL that was given for the specific image when uploading to your files. Currently this is the only workaround. Our developers are currently working on this issue!