@girish, thanks for following up. I tried a handful of things:
Stop & start of the Lychee app.
Full Reboot of the Cloudron Server.
Uninstall and reinstall of the Lychee app.
Increased allocated memory.
I believe it was due to the allocated memory. I increased it from 256MB to 1GB this morning and everything is working fine. I can do some further testing when I have time to see if I can reproduce it. Either way, I'm now able to upload a photo (or multiple photos simultaneously). It would error uploading a single 5MB photo before this change.