Cmd often encounters database link exceptions, with a page displaying a 500x error code

## Describe the bug

Cmd often encounters database link exceptions, with a page displaying a 500x error code

## Platform
- Device: [Desktop]
- OS: [Windows]
- Browser and version: [Chrome]
- Version: [ v1.6.0]

Start by reproducing the failed image upload on Windows with Chrome using version 1.6.0, then inspect the database connection error and the resulting 500 response. Done means the upload no longer exposes a database-link failure as a 500x page, with a regression test covering the failure if the relevant test area can be identified.

Written by the indexing model from the issue text.