Methodology

How the sizes, crop zones and audit results on Better Header are produced, so you can judge how far to trust them.

Upload sizes come from the platforms

Every pixel size, file format and file-size limit in a guide is read from the platform's own help documentation. Guides with hand-written copy name the help page and the date it was checked under the FAQ. When a platform changes a number we update the guide, the audit data and the log below.

Crop zones come from device profiles

Platforms do not publish where their interface covers a header, so that part is ours. Each device profile records how wide and tall the header renders on that screen and where each overlay sits (profile photo, status bar, Dynamic Island, buttons, captions), stored as fractions of the header so they scale with the image. An audit draws those zones over your file and reports any overlap with the areas you marked as important.

Devices we render on (21)

  • Apple Mail iPhone phone
  • Desktop (1080p) desktop
  • Desktop (1440p) desktop
  • Discord unfurl desktop
  • Email client (Apple Mail) desktop
  • Email client (Gmail mobile) phone
  • Gmail desktop desktop
  • Gmail mobile phone
  • Outlook desktop desktop
  • Phone (Mobile) phone
  • Pixel 9 Pro phone
  • Slack unfurl desktop
  • TV (4K) desktop
  • Tablet tablet
  • Twitter unfurl desktop
  • iMessage rich link phone
  • iPad Pro 12.9" tablet
  • iPhone 16 phone
  • iPhone 16 Pro phone
  • iPhone 16 Pro Max phone
  • iPhone SE phone

Platforms covered

X (Twitter), LinkedIn (Personal), LinkedIn (Company), YouTube, Facebook (Personal), Twitch, TikTok video cover, Substack publication header, GitHub social preview image, Email signature banner.

Limits

Platforms change their layouts without notice, and apps render slightly differently by version and by accessibility text size. Treat an audit as a strong check, not a guarantee, and look at the live profile once after you publish.

Spec changelog

  • : LinkedIn company page cover corrected to 1512 × 256 (LinkedIn Help a563309). The guide previously said 4200 × 700, which was wrong.