Compress HEIC Images for Mailchimp
Mailchimp email campaigns require properly sized, email-safe images. Optimized images improve email deliverability, load faster in all email clients, and increase engagement rates. High Efficiency Image Format — the default photo format on iPhones and modern Apple devices. Excellent compression. Use ImageSmith to compress your HEIC images to the ideal file size for Mailchimp — target under 10,240KB for optimal performance. Processing is fully browser-based — no server uploads, no privacy risk.
Recommended format
JPEG
Max file size
10,240KB
Dimensions
600px wide for email body, 1200×600 for header banners
✓Email content area is 600px wide — design at 600px or 1200px (2× Retina)
✓Keep individual images under 200KB for fast email loading
✓Avoid WebP — Outlook does not support it in emails
✓Test emails across clients (Gmail, Outlook, Apple Mail) before sending