You designed the perfect social card image. Bold colours, clean text, the product front and centre. You post the link on Twitter and it looks great. Then someone shares it on LinkedIn and the headline text is cropped off. A team member drops it in Discord and the image is stretched. Your designer asks why the Facebook version looks blurry.
This isn't a bug in your image. It's a fundamental mismatch between what you exported and what each platform expects. Every social network has its own rules for how it renders the og:image tag — different dimensions, different aspect ratios, different minimum sizes, and different cropping behaviour. If you don't know the rules, you're guessing. And guessing means your link preview looks great in one place and broken everywhere else.
What Is og:image and Why Does It Matter?
The og:image meta tag tells social platforms which image to display when someone shares your link. It's part of the Open Graph protocol — the HTML metadata standard that controls link preview cards across Twitter/X, LinkedIn, Facebook, Discord, Slack, iMessage, and dozens of other platforms.
When a platform's crawler visits your URL, it reads the og:image tag and downloads the image at that URL. The crawler then resizes, crops, and renders it according to that platform's own display rules. You don't get to control the rendering step — only the source image. That means if your source image isn't optimised for the platform's rules, the result is out of your hands.
This matters because the preview image is the single biggest factor in whether someone clicks your link. Eye-tracking studies consistently show that users look at the image first, then the title, then the description. A sharp, relevant preview image can double or triple your click-through rate compared to a missing or poorly cropped one.
The Universal Safe Size: 1200 × 630px
If you only remember one number from this article, make it this: 1200 × 630 pixels. This is the one size that works acceptably across every major platform. It's a 1.91:1 aspect ratio — the same ratio Facebook originally specified for shared link images, and the ratio that Twitter, LinkedIn, and most other platforms have converged on.
At 1200 × 630px, your image will:
- Display as a full-width large image card on Twitter/X without cropping
- Render cleanly in LinkedIn feed posts with proper proportions
- Show correctly in Facebook shared links and Open Graph debugger
- Look good in Discord embeds (Discord prefers 16:9 but handles 1.91:1 gracefully)
- Display properly in Slack unfurls, iMessage link previews, and WhatsApp shares
The key word is "acceptably." 1200 × 630 is a compromise — it's not the ideal size for every platform, but it's the only size that doesn't look broken on any of them. If you're creating one image to share across multiple channels, this is the size to use.
Platform-by-Platform Breakdown
If you want to go beyond the universal size and optimise for specific platforms, here's what each one expects.
Twitter / X
Twitter renders two types of link cards: summary cards (small square thumbnail + text) and summary_large_image cards (full-width image above the text). You almost always want the large image card — it takes up more visual real estate in the timeline and gets significantly more engagement.
- Recommended size: 1200 × 630px (1.91:1 ratio)
- Minimum size: 300 × 157px — below this, Twitter may fall back to a summary card
- Maximum file size: 5 MB
- Supported formats: JPG, PNG, GIF, WebP
- Cropping behaviour: Images wider than 1.91:1 get cropped from the centre. Images taller get cropped top and bottom. Twitter is aggressive about cropping — keep important content in the centre 80% of the image
Twitter also reads twitter:image as a platform-specific override. If you set both og:image and twitter:image, Twitter uses its own tag. This lets you serve a Twitter-optimised image while keeping a different og:image for other platforms — though in practice, 1200 × 630 works well enough that most people don't bother with separate tags.
LinkedIn renders link previews in two contexts: feed posts (where the image appears above the title and description) and messages (where it's a smaller inline card). The feed post format is what matters for most marketers.
- Recommended size: 1200 × 627px (1.91:1 ratio)
- Minimum size: 200 × 200px — below this, LinkedIn may not show an image at all
- Maximum file size: 5 MB (LinkedIn's post inspector may reject larger files silently)
- Supported formats: JPG, PNG
- Cropping behaviour: LinkedIn crops to 1.91:1 from the centre. Images with a different ratio will lose content on the edges
LinkedIn's biggest quirk is its aggressive caching. Once LinkedIn scrapes your og:image, it caches the result for days — sometimes weeks. If you update the image and reshare the link, LinkedIn will often show the old version. The only way to force a refresh is to use LinkedIn's Post Inspector tool (linkedin.com/post-inspector/) to manually re-scrape the URL before sharing.
Facebook was the originator of the Open Graph protocol, so its support is the most complete. Link previews in the News Feed show the image prominently above the title and description.
- Recommended size: 1200 × 630px (1.91:1 ratio)
- Minimum size for large image: 600 × 315px — below this, Facebook renders a small square thumbnail instead
- High-resolution display: For retina screens, Facebook recommends 1200 × 630 as a minimum — not 600 × 315
- Maximum file size: 8 MB
- Supported formats: JPG, PNG, GIF, WebP
Like LinkedIn, Facebook caches aggressively. Use the Facebook Sharing Debugger (developers.facebook.com/tools/debug/) to clear the cache and force a fresh scrape. Facebook will also warn you in the debugger if your image is below the recommended size or if og:image is missing entirely.
Discord
Discord renders links as rich embeds with a coloured accent bar on the left. The embed includes the site name, title, description, and image. Discord's image rendering is more flexible than other platforms but has its own rules.
- Preferred aspect ratio: 16:9 (1280 × 720px is ideal)
- Also works well: 1.91:1 (1200 × 630px) — Discord will add slight letterboxing but it looks fine
- Maximum embed image width: 400px in the rendered embed (Discord downscales larger images)
- Maximum file size: Discord downloads up to 8 MB from the og:image URL
- Supported formats: JPG, PNG, GIF (animated GIFs play inline), WebP
Discord has a unique behaviour: if you include both og:image and a Twitter Card image, Discord often prefers the og:image. Discord also reads the theme-color meta tag to set the accent bar colour on the left side of the embed — a nice detail most other platforms ignore.
Choosing the Right Format
The image format you choose affects both quality and loading speed. Here's when to use each one.
- PNG — Best for images with text, logos, screenshots, or sharp edges. Lossless compression means no artefacts around text. Larger file size but guaranteed sharpness. Use this when your OG image includes a headline overlay or brand elements.
- JPG — Best for photographs and complex images with lots of colour gradients. Smaller file size than PNG at comparable visual quality. Use this for product shots, lifestyle images, or any photo-heavy preview.
- WebP — Modern format supported by most platforms (Twitter, Discord, Facebook all accept it). Offers better compression than both PNG and JPG. LinkedIn support is inconsistent — test before committing to WebP-only.
- GIF — Supported but rendered as a static frame on most platforms (only the first frame is shown). Discord is the exception — it will play animated GIFs inline. Avoid for OG images unless you specifically target Discord.
For most use cases, PNG is the safest choice when your image contains text, and JPG is the safest choice for photos. If you're serving a general-purpose OG image across all platforms, PNG at 1200 × 630 is the gold standard.
Common Mistakes That Break Your Preview Image
Even if you get the dimensions right, these mistakes can still make your OG image look bad.
- Text too close to the edges — Every platform crops slightly differently. Keep all important text and logos within the centre 80% of the image. A 60px margin on all sides is a good rule of thumb.
- Using a square image — A 1:1 image will be aggressively cropped on every platform that expects 1.91:1. You'll lose nearly half the image. Always use landscape orientation.
- File too large — Images over 5 MB may timeout during crawling. Some platforms silently fail and show no image at all. Keep files under 1 MB when possible — compress with tools like TinyPNG or Squoosh.
- Serving the image over HTTP — Most platforms require HTTPS for og:image URLs. An HTTP image URL will be silently ignored by Twitter and LinkedIn.
- Caching a broken version — If you shared a link before the og:image was set up, the platform cached a blank preview. You need to actively clear the cache using each platform's debug tool before resharing.
- Using a CDN that blocks crawlers — Some CDN configurations block non-browser user agents. Social platform crawlers have specific user agents (Twitterbot, LinkedInBot, facebookexternalhit) that must be allowed through.
How to Preview Before You Share
Never share a link without checking the preview first. Each platform offers a debug tool that lets you see exactly what the crawler sees.
- Twitter/X — Card Validator (cards-dev.twitter.com/validator) — paste your URL and see the rendered card
- LinkedIn — Post Inspector (linkedin.com/post-inspector/) — scrapes the URL and shows the preview with diagnostics
- Facebook — Sharing Debugger (developers.facebook.com/tools/debug/) — shows all OG tags found, warns about issues, and lets you force a re-scrape
- Discord — Paste the link in a test server. Discord scrapes in real time, so what you see is what everyone sees
If you're using Prelinq to create your link previews, you can skip the per-platform debugging. Prelinq's builder shows you a live preview of how your card will render on X, LinkedIn, Discord, and the default card format — side by side — before you publish. The image you upload is automatically served at the right size, over HTTPS, with proper caching headers.
The Fast Track: Let Prelinq Handle It
If you're sharing links you don't own — affiliate links, partner content, news articles — you can't control the destination site's og:image. That's where Prelinq comes in. Instead of hoping the destination has good OG tags, you create a Prelinq with your own image, title, and description. Social platforms see your metadata; visitors get redirected to the original URL.
Prelinq accepts uploads up to 20 MB (Business plan) and serves them optimised for social sharing. You can also paste any image URL or search Giphy for a GIF — whatever fits your preview strategy. The point is that you're in control of the image, not the destination site.
Quick Reference Cheat Sheet
Bookmark this for your next campaign.
- Universal safe size: 1200 × 630px (1.91:1 ratio)
- Twitter large card: 1200 × 630px — keep text in centre 80%
- LinkedIn feed post: 1200 × 627px — cache is aggressive, use Post Inspector to refresh
- Facebook shared link: 1200 × 630px — minimum 600 × 315 for large format
- Discord embed: 1280 × 720px ideal (16:9) — 1200 × 630 also works
- Format: PNG for images with text, JPG for photos
- File size: Under 1 MB ideal, under 5 MB maximum for all platforms
- Always use HTTPS for the image URL
- Always preview with platform debug tools before sharing