Why this happens
Platforms like Facebook, LinkedIn, and Slack use the og:image dimensions to decide how
to display the preview. When the image is too small:
- It is rendered as a small thumbnail beside the title rather than a full-width card
- Some platforms skip the image entirely if it falls below their minimum threshold
- The preview looks low-resolution on high-density displays if the image was already small and gets upscaled
The original Open Graph spec recommends 1200×630 at a 1.91:1 ratio. Images below roughly 600×315 trigger thumbnail-only rendering on most major platforms.
Run the free Open Graph Checker to see which tags are missing, invalid, or too small.
The size to use
Use 1200×630 pixels (1.91:1 ratio). This is the standard across Facebook, LinkedIn, Slack, and most other platforms that read Open Graph tags.
- Minimum to get a large card: roughly 600×315
- Recommended for sharp display: 1200×630
- File format: JPEG or PNG; keep file size under ~1 MB (ideally ~200–500 KB)
Platforms crop the image to fit their card layout, so keep important content centred and away from the edges.
How to check
Paste your URL into the Open Graph Checker. It shows the
og:image URL, fetches the image, and reports its dimensions. If the dimensions are
below 600×315, that is the cause of the thumbnail rendering.
If you need to generate a properly sized image, the OG Image Generator produces a 1200×630 PNG ready to upload.
How to fix
- Replace the current image with one that is at least 600×315 — ideally 1200×630.
- Host it at a public, absolute HTTPS URL.
- Update the
og:imagetag in your page<head>to point to the new image. - Re-check with the Open Graph Checker to confirm dimensions.
- Clear any platform caches: LinkedIn Post Inspector, Facebook Sharing Debugger, etc.
See Open Graph image size for a full breakdown of per-platform requirements.