This is a carryover from T183310.
Behavior:
- upload a 3D file
- as soon as the upload is complete, click the filename to go to the new File page
- Placeholder image appears while large preview image is generated
- roughly 5 to 30 seconds later (depending on size of file, etc), "3D" appears above the placeholder (see image)
- some time after that, the full preview image loads{F13351482}