# Open Graph Preview: Check the Share Card Before You Hit Post > LinkedIn and Slack will invent a title if your OG tags are wrong. Preview the card from your HTML before the URL goes live. - **URL**: https://brytetools.com/post/open-graph-preview-before-you-share - **Markdown summary**: https://brytetools.com/llms/posts/open-graph-preview-before-you-share.md - **Meta description**: Preview Open Graph title, description, and image from pasted HTML. Free OG preview for agencies and founders — no upload of your site. ## Article You published the article, pasted the URL in Slack, and the card shows a cropped screenshot of the footer plus the site name as the title. That is not “the algorithm.” That is missing or relative Open Graph tags. An open graph preview lets you catch the card while you still have the HTML in front of you — before crawler caches freeze a bad image for a week. ## What the share card actually reads Most networks look for: - og:title — the headline on the card - og:description — the supporting line - og:image — absolute https URL, ideally ~1200×630 - og:url — canonical page URL If those are absent, scrapers fall back to and a random image. That is how you get a hero crop of a cookie banner. ## Preview without deploying a “test tweet” Paste the page HTML into [BryteTools Open Graph Preview](https://brytetools.com/tools/og-preview). You get a generic link-preview card similar to Facebook, LinkedIn, and Slack. Tags are parsed locally. Image URLs still load from their host when you preview — that is expected for absolute og:image assets. Relative paths like /images/share.png will not load in the preview or on most crawlers. Make the image URL absolute. ## Image rules that survive cropping SpecPractical target Size~1200×630px Protocolhttps, publicly fetchable Safe zoneKeep type out of the outer 10% — networks crop differently File weightCompress; huge PNGs time out on crawlers After you fix the asset, compress it with [Image Compressor](https://brytetools.com/tools/image-compressor) so the crawler is not waiting on a 4MB PNG. ## The rest of the on-page pass OG is one slice of the pre-publish audit. Title length, meta description, and canonicals still belong in [Meta Tag Inspector](https://brytetools.com/tools/meta-tag-inspector). Structured data errors are a separate pass with [Schema JSON-LD Validator](https://brytetools.com/tools/schema-validator). When the URL is paid traffic, tag it with [UTM Link Builder](https://brytetools.com/tools/utm-builder) so the pretty card is also a measurable click. ## Caches: why the old image will not die Facebook and LinkedIn cache aggressively. Changing the file in place on the same URL often does nothing. Use a new image URL (query string or new filename), then re-scrape in each debugger. Preview locally first so you are not burning debugger credits on typos. ## FAQ What platforms does Open Graph Preview simulate?A generic card similar to Facebook, LinkedIn, and Slack. Exact fonts and crops still differ per network. Why doesn’t my og:image show?It must be an absolute https URL. Relative paths fail in preview and on crawlers. What if the page has no Open Graph tags?The tool falls back to <title> and the meta description so you can see how sparse the card would look. Recommended image size?About 1200×630px. Test after deploy because caches stick. Is HTML uploaded for the preview?No. Parsing is local. Images load from their host when you preview an absolute URL. ## Try it now [Preview your share card free →](https://brytetools.com/tools/og-preview) Fix the tags once. Stop debugging in the comments. ## Site context BryteTools provides free private browser tools. See https://brytetools.com/llms.txt for the full catalog.