Step-by-step instructions
- 1
Identify how many images you're sending and their total size
Select all the images you plan to attach. Right-click → Properties (Windows) or Get Info (Mac) to see total size. If total is under 5 MB: you're probably fine as-is. If 5–20 MB: consider basic compression. If over 20 MB: definitely compress or consider cloud sharing instead.
Go to converter - 2
Convert HEIC to JPG first (iPhone photos)
iPhone HEIC photos can't be opened on all devices, and they're not as compressed as they look — a 3 MB HEIC may become 5–8 MB when converted to JPG at full quality. Use formatdrop.com/heic-to-jpg to convert HEIC to JPG. At this stage you're also fixing the compatibility issue — most email recipients can't open HEIC files anyway.
- 3
Reduce image resolution if it's excessively high
A 12 MP photo at 4000×3000 pixels is much larger than any email recipient needs to view on screen. Scaling it down to 1920×1440 (still a very usable 2.8 MP) reduces file size by 75% before any other compression. Use FormatDrop's image converter to resize: select your JPGs, set max width to 1920px, and download.
- 4
Compress JPG quality to 70–80%
Re-saving a JPG at 70–80% quality produces a file that looks identical to the original in email viewing but is significantly smaller. The human eye cannot detect JPG compression at quality 80 in typical image viewing. Open formatdrop.com/image-converter, select JPG output with quality 80, and process your images.
- 5
Consider cloud sharing for large batches
If you're sending 10+ photos, consider Google Drive, Dropbox, or iCloud Links instead of attachments. These services send a single link rather than 30 MB of attachments. To share: upload all images to a Google Drive folder, right-click → Share → 'Copy link', and paste the link in your email. Recipients click the link to view/download rather than waiting for large attachments.
Why convert HEIC to JPG?
The reason images seem so much larger in email than expected is multi-layered. First, email clients often encode attachments in Base64 before transmission, which increases file size by 33% beyond the raw file data. Second, mobile email apps may preview all attachments before download — meaning large images create loading delays even before the recipient downloads them. Third, many corporate email servers have strict size limits enforced at the server level rather than the client — if you exceed the limit, the email bounces without a clear error message to the recipient. The practical standard for email images: keep each image under 1 MB, and the total attachment under 5 MB, to ensure deliverability across the widest range of email systems. For high-quality sharing of many images, cloud storage links are the professional standard.
Your files never leave your device
FormatDrop runs the conversion engine entirely inside your browser using WebAssembly. No file upload. No server. Nothing stored. You can verify this by opening DevTools → Network tab and watching: zero upload requests.
Frequently asked questions
What is the maximum email attachment size?
Can I send photos at full quality via email?
How do I email multiple photos without them being too big?
No account. No upload. Works in any browser.