Quick answer
Most email clients cap attachments at 25MB. A single photo from a modern phone is 3-8MB, so attaching four or five photos can hit that limit. Compress each photo to under 1MB by resizing to 1200px wide and saving as JPG at 85% quality. The recipient will not see any difference.
Why email attachments are too large
Phone cameras keep getting better, and file sizes keep growing with them. An iPhone 15 photo is typically 4-6MB. A Samsung Galaxy S24 shoots 50MP images that reach 8-12MB. PNG screenshots from a retina display run 2-5MB each.
Gmail, Outlook, and Yahoo all enforce a 25MB attachment limit. Some corporate mail servers cap at 10MB. Even when the total fits, large attachments slow down sending and clog the recipient's inbox storage.
How to compress images for email
1. Resize to actual display dimensions
A 4000x3000 photo contains 12 million pixels. Most email clients display images at 600-800px wide. Resizing to 1200px wide (good for retina screens) cuts the pixel count by 90% and the file size drops proportionally. A 6MB photo becomes 400-600KB.
2. Convert to JPG
If you are sending a photo (not a screenshot with text), JPG is the right format. PNG files preserve every pixel but create files 5-10x larger than JPG for photographic content. A 5MB PNG photo becomes 800KB as JPG with no visible difference.
3. Set quality to 85%
JPG quality below 80% starts showing compression artifacts, especially around edges and text. At 85%, the file is 60-70% smaller than the original with no visible degradation. Going higher than 90% adds file size without any perceptible improvement.
Recommended sizes by use case
- Email body images: 800px wide, JPG 85%. Target: 100-300KB each.
- Photo attachments: 1200-1600px wide, JPG 85%. Target: 300KB-1MB each.
- Screenshots: Keep as PNG for text clarity, resize to actual display width. Target: under 500KB.
- Documents and scans: 1200px wide, JPG 90% (higher quality preserves text). Target: 200-500KB.
Common questions
Does compressing reduce image quality?
At 85% JPG quality, the difference from the original is invisible to the naked eye. Side-by-side, you cannot tell which is the original. Below 70%, artifacts become noticeable around hard edges and fine details.
Can I compress multiple photos at once?
Yes. The Image Optimizer supports batch processing with Pro. Drop up to 50 files, set your target size, and download a single ZIP. Useful for sending a full event gallery or product photo set.
What if the recipient needs full resolution?
Use a file sharing link (Google Drive, Dropbox, WeTransfer) instead of email attachments. These services handle large files without compression. For print-quality photos, the recipient will need the original dimensions anyway.
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