Best Image Format for Email Attachments: JPG, PNG, or Something Else?
You are attaching an image to an email and wondering which format to use. The answer depends on what the image is and who is receiving it. Choose wrong and your recipient sees a broken attachment, an unreadable file, or a 15MB email that clogs their inbox. Here is what works, what does not, and why.
JPG: the safest choice for photos
JPG is the universal image format. Every email client on every platform can open, display, and preview JPG files. If you are sending photos — vacation pictures, product shots, headshots, event photos — JPG is always the right choice.
JPG's main advantage for email is file size. A 12-megapixel photo is about 3-5MB as JPG at good quality, compared to 15-25MB as PNG. Smaller files mean faster sending, faster receiving, and no bounced emails from size limits.
The one downside of JPG is that it does not support transparency. If you need a logo on a transparent background, use PNG. For everything else, JPG wins.
PNG: best for screenshots and graphics
PNG preserves sharp edges and text perfectly, making it the right choice for screenshots, diagrams, charts, logos, and any image with text content. JPG compression creates visible artifacts around sharp edges and text, making screenshots look fuzzy.
The tradeoff is file size. A full-screen screenshot as PNG can be 2-5MB, while the same image as JPG at 85% quality would be 300-600KB. For most email purposes, the larger file is worth it because readability matters more than size when you are sharing a screenshot of a bug report or a design mockup.
Formats to avoid in email
HEIC/HEIF: iPhones shoot in HEIC by default, and many people try to email these directly. The problem is that Windows does not support HEIC natively, and many email clients cannot preview it inline. If you send a HEIC file, there is a good chance your recipient will see a generic file icon and not know how to open it. Always convert HEIC to JPG before emailing.
WebP: While WebP works in browsers, email client support is inconsistent. Outlook desktop cannot display WebP images inline. Many corporate email systems strip or block WebP attachments. Do not use WebP for email attachments unless you know the recipient's email client supports it.
TIFF: TIFF files are enormous (30-100MB for a single photo) and most email clients cannot preview them inline. TIFF is for print workflows, not email. Convert to JPG before sending.
BMP: Uncompressed and huge. A 1920x1080 BMP is about 6MB versus 300KB as JPG. There is no reason to email a BMP in 2026.
RAW (CR2, NEF, ARW): Camera RAW files are 20-60MB each and require specialized software to open. Never email RAW files unless the recipient specifically asked for them and knows what they are.
Quick reference: which format for what
Photos and images with gradients: JPG
Screenshots with text: PNG
Logos needing transparency: PNG
iPhone photos: Convert HEIC to JPG first
Scanned documents: PDF (not an image format, but better for multi-page scans)
Email attachment size limits
Every email provider has a maximum attachment size. Exceeding it means your email bounces or the attachment is silently dropped:
- Gmail: 25MB total attachments
- Outlook / Microsoft 365: 20MB (some enterprise configs allow 35MB)
- Yahoo Mail: 25MB
- iCloud Mail: 20MB (uses Mail Drop for larger files, which sends a download link)
- ProtonMail: 25MB
These limits are for total attachment size, not per file. If you attach five 5MB images to a Gmail, that is 25MB and you are at the limit. Compress your images before attaching, especially if you are sending multiple photos.
How to compress images for email
The fastest approach: upload your images to the image compressor, set quality to 80%, and download. For most photos, this cuts file size by 70% with no visible quality loss at the sizes people view email attachments.
If you are sending many images, consider these alternatives:
- Zip the images: Multiple compressed JPGs in a single ZIP file is cleaner than five separate attachments.
- Use a sharing link: Google Drive, Dropbox, or iCloud shared links bypass email size limits entirely. Upload the full-quality images and share the link in your email.
- Resize before compressing: A 4000px wide photo is overkill for email viewing. Resize to 1920px or 1200px wide, then compress. This makes the biggest difference in file size.
iPhone photos: the HEIC problem
If you take a photo on an iPhone and email it, iOS usually converts it to JPG automatically. But this is not always reliable — AirDropped photos stay as HEIC, and some email apps attach the original HEIC file. If your recipient is on Windows or Android and reports they cannot open your photo, the HEIC format is almost certainly the issue.
You can change your iPhone's camera to shoot in JPG directly (Settings > Camera > Formats > Most Compatible), or convert HEIC to JPG before sending.
Compress images for email
Reduce image file sizes by up to 80% while keeping them sharp. Works with JPG, PNG, and WebP. No upload to any server.