Issue #1661814 by kbasarab, lewisnyman, Ken Hawkins, mcjim, JohnAlbin, h4rrydog: Make 'in maintenance' Seven use a responsive design.

- Patch #927138 by rasmusluckow, douggreen, marcingy, h4rrydog, swing4cat: Fail image generation with 404 instead of 500, when source file is missing.