What is an og:image?
In short
- An og:image is the preview picture a chat app or social platform shows when someone pastes your link.
- It comes from an Open Graph tag in the page, a small piece of metadata that apps read.
- A good preview makes people much more likely to click a shared link.
An og:image belongs to the Open Graph protocol, a set of metadata tags that tell other apps how to present your link. When you paste a URL into Slack, iMessage, WhatsApp, or LinkedIn, the app fetches the page, reads its Open Graph tags, and builds a small card with a title, a description, and an image. The og:image is that picture. Without one, your link unfurls as a bare line of text that is easy to scroll past.
The recipient sees the preview before deciding whether to click, so it carries a lot of weight. NudgeHost generates a sensible preview for hosted files, which makes a link look intentional rather than broken. When you share a PDF by link, the preview reflects the document. A deck you send to a client as a link lands in their inbox with a clean card.
On a page you build yourself, you set the og:image with one meta tag pointing at an image about 1200 by 630 pixels. NudgeHost handles the preview for hosted files. Hosting costs nothing, and you can upload a file with no account and paste the link into a chat to see the card for yourself.
Frequently asked questions
Why does my shared link have no preview image?
Either the page is missing an og:image tag, or the app is still showing an old cached preview. Pages hosted on NudgeHost include a sensible preview by default.
What size should an og:image be?
About 1200 by 630 pixels works across Slack, iMessage, LinkedIn, and most other platforms, which crop or scale to that ratio.
Can I set a custom preview image?
On a page you build, yes, with a meta tag pointing at your image. Hosted files get an automatic preview based on the file.
Put it into practice.
Drop a file and get a shareable link in seconds. Free, no card needed.