How to Resize Images for Email: The Right Dimensions and File Size

Images in emails are tricky — too large and they break layouts, trigger spam filters, or never load on slow connections. Too small and they look pixelated on Retina screens. Here are the dimensions and file sizes that work across all email clients in 2026.

Recommended Image Dimensions for Email

• Email body width: 600px — this is the standard email width used by virtually every email client since Outlook 2003
• Hero / banner image: 600×200px to 600×300px
• Inline product images: 300×300px or 600×400px
• Email signature logo: 200×50px to 300×75px (keep this under 20KB)
• CTA button background: 200×50px
• Always resize images to 600px wide before embedding them in email templates.

Recommended File Sizes for Email Images

• Total image weight per email: Under 1MB total — many email clients stop downloading images after this threshold
• Individual hero image: Under 200KB — use Compress to 200KB
• Product images: Under 100KB each — use Compress to 100KB
• Signature logo: Under 20KB — use Compress to 20KB
• Inline icons / small graphics: Under 10KB each

Email Clients and Image Support

• Gmail: Displays all common formats (JPG, PNG, GIF). Does not support WebP fully.
• Outlook (Windows): JPG and PNG recommended. Does not support animated GIF in newer versions. Avoid WebP.
• Apple Mail: Supports everything including WebP and HEIC.
• Mobile email apps: Generally support JPG and PNG.
• Recommendation: Use JPG for email images. PNG for logos and transparent backgrounds. Avoid WebP in email — support is inconsistent.

Why Email Images Sometimes Do Not Display

• Many email clients block images by default — always include descriptive alt text
• Images hosted on unsecured (HTTP) servers are blocked in many clients — always use HTTPS
• Attachments over 5–10MB get blocked by corporate mail servers
• Filenames with spaces or special characters can cause display issues in some clients
• Very large pixel dimensions (over 2000px) can cause layout issues in Outlook

How to Check Your Email Image Size

Before sending, use ImageResize.co to check and resize your images. Enter the exact pixel dimensions you need, download, then use Compress to 200KB to hit the file size target. The entire workflow takes under two minutes.