Yes, as per these recent topics:
- https://itch.io/t/1222826/image-upload-server-borked
- https://itch.io/t/1222507/cant-upload-cover-images-or-screenshots
- https://itch.io/t/1222266/cant-upload-cover-image-500-internal-server-error
- https://itch.io/t/1222051/screenshots-broken-on-the-store-pages
Things should be back to normal as of this writing though.