Recommended image dimensions

Use 1200 x 630 pixels (1.91:1 aspect ratio). This is the standard OG image size and displays well in Teams unfurl cards.

Side-cropping behavior

Teams trims the left and right edges of images in unfurl cards. The amount varies between chat vs. channel and desktop vs. mobile. Keep important content centered with safe margins on all sides.

Supported formats

• JPEG – best for photos, good size-to-quality ratio
• PNG – best for graphics, logos, and text

Formats to avoid

• SVG – Teams returns 415 Unsupported Media Type. A common gotcha for sites using SVG OG images.
• WebP – not officially recommended. JPEG or PNG are safer across all Teams clients.

Image proxying

Teams re-proxies images through Microsoft’s CDN rather than hotlinking. This means:

• Your server must be publicly accessible at crawl time
• Images are cached on Microsoft’s proxy independently from the metadata cache
• Updating the image at the same URL won’t immediately update the preview
• HTTP (non-HTTPS) images may fail to load

Image URL requirements

• Absolute URL with full scheme and domain
• Accessible without authentication
• Served over HTTPS
• Fast to respond – the Microsoft proxy times out on slow servers

Designing for Teams unfurls

The layout varies between desktop, mobile, and web clients, with the image alongside or below text. Use 1200x630, center your content, stick to JPEG or PNG, and keep file sizes reasonable.