2026-08-09
Email attachment size limits are the most annoying invisible rule in sending: Gmail caps at 25MB, Outlook at 20MB, plenty of corporate mailboxes at 10MB or less, and a single phone photo can already be 8MB. This post covers the practical way to reduce image size for email in 2026: browser-local compression, no upload, no sign-up, done in 30 seconds.
Compress toward a number, not a guess. Limits vary a lot: Gmail 25MB total, Outlook/Office 365 20MB, Yahoo 25MB, corporate Exchange commonly 10MB, and many job-application or form systems accept 5MB or even 100KB per file. If an email bounces, it names the limit; use that number.
To take an 8MB phone photo down to sendable, work in levels. Level one: a browser-local compressor at quality 80-85% usually lands 1-2MB. Level two: resize the long edge to 1920px, which is plenty for on-screen viewing and halves the file again. Level three: switch formats, WebP is about 70% of JPG at equal quality, but recipients' mail clients may not preview it, so stick with JPG for formal attachments.
Compressing dozens of images one by one is a waste of an afternoon. Browser-local tools queue multiple files automatically, faster than upload-based compressors that force one round trip per image. Check the total against the limit, and if it is still over, drop one more quality notch. For sensitive files (IDs, contracts), only use local processing, never an upload-based tool.
25MB total across all attachments. Emails over that bounce with a size limit exceeded error. Sending under 20MB leaves comfortable margin.
Drop quality to 75-80% and resize the long edge to 1280px. A JPG treated that way usually lands at 80-150KB; if still over, go to 64% quality or 1024px. Browser-local tools show the resulting size instantly.
WebP is smaller, but recipient mail clients may not preview it and some systems reject it. Use JPG for formal attachments; WebP is for the web.
Quality 80% with a 1920px long edge is practically indistinguishable on screen. Blur comes from over-compression (below 60%) or shrinking too far. Preview before sending.