**Motivations:**
- Document the issue with nostrimg.com returning HTML instead of JSON
- Explain possible root causes and solutions
- Provide diagnostic steps for troubleshooting
**Root causes:**
- Missing HTTP headers (Accept, User-Agent)
- Possible incorrect endpoint URL
- Possible authentication requirements
- Endpoint may be unavailable or changed
**Correctifs:**
- Added Accept and User-Agent headers
- Improved HTML error detection and classification
- Enhanced error messages and logging
**Evolutions:**
- None
**Pages affectées:**
- fixKnowledge/nostrimg-html-response-error.md (new)
