Rules / og-image-content-type-mismatch · ruleset 2026-07
Image Content-Type does not match actual format
| Rule id | og-image-content-type-mismatch |
|---|---|
| Severity | error |
| Category | Images |
| Platforms | all platforms |
| Needs human | no |
What this is
Image Content-Type does not match actual format. OGKit rule og-image-content-type-mismatch (error). The id is a public API for the docs URL and CI --disable key; do not rename it.
Search phrases that should land on this page:
Image Content-Type does not match actual formatcontent-type mismatch og:imagewrong MIME type image
Why it matters
Lying Content-Type or extension mismatches cause some crawlers to reject the image even when the bytes are valid.
Which platforms are affected
All OGKit platform profiles, including major social, chat, and search crawlers that consume these tags.
Platform-specific crawler budgets and field priority live in the platform behaviour reference.
How to reproduce
- Compare the HTTP Content-Type of the image URL with the actual file signature (magic bytes).
- Serving JPEG as image/png (or vice versa) fails this check.
How to fix
Serve the image with the correct Content-Type (image/jpeg, image/png, image/webp, image/gif) matching the file magic.
No single template snippet applies; use the measured and expected values in an OGKit finding.