How to compress an image to fit an email attachment limit
Email attachment limits are surprisingly low. Gmail caps you at 25 MB total per email, Outlook 20 MB, most corporate Exchange servers 10 MB. A single iPhone Live Photo or modern DSLR JPG often blows past those limits on its own. This guide shows how to compress an image down to a manageable size in your browser — usually 70–90% smaller than the original — without losing visible quality for screen viewing.
Three common situations. (1) You took a photo of a paper document with your phone — the JPG is 8 MB and the recipient's spam filter rejects emails over 5 MB. (2) You're emailing a contractor 6 photos of a renovation site — together they're 50 MB and the email bounces. (3) You're invoicing a client and want to attach a high-res scan of a signature page — the original is 15 MB and Gmail truncates the preview thumbnail. In all three, compressing the image to 1–3 MB solves the problem with zero visible quality loss for typical email viewing.
Step by step
Open the image converter
Even though we call it a converter, it doubles as a quality-controlled compressor. Drop the image, lower quality, download the lighter version.
Drop your photo
JPG, PNG, HEIC and WebP are accepted. Multiple files at once is fine for batch compression.
Keep the same format (or convert HEIC to JPG)
If your file is already JPG, keep it as JPG to preserve compatibility. If it's HEIC (iPhone), switch to JPG so the recipient can open it without an Apple device.
Drop quality to 70–80%
This is the magic range. 70% quality is visually identical to 100% on a phone screen and a normal monitor at typical viewing distances. The file gets 60–80% smaller. For zoom-in inspection (legal documents, fine print, photos for editing), bump to 85%.
Download and attach
Verify the file size in your downloads folder before attaching. If still too large, drop quality to 60% or resize the image dimensions (Image Crop tool) to e.g. 1920px wide.
Compress your image to email-friendly size right now.
Common pitfalls
- Compressing a PNG to a smaller PNG often doesn't help much — PNG is lossless. Convert to JPG instead for photos, or to WebP for graphics with transparency.
- Re-saving a JPG at lower quality is one-way. Each re-save degrades a tiny bit. Don't do it multiple times in a row — keep the high-quality original somewhere and re-compress from it for each email.
- Some email clients (older Outlook) decompress and re-compress attachments automatically. Your carefully tuned 1.5 MB JPG might land at 2.2 MB in the recipient's inbox. Test with a sent-to-yourself first if you're tight on budget.
- Quality settings below 50% start showing visible blocking artefacts. If you need to go that small, compress less aggressively but resize dimensions instead — visually it's much cleaner.
FAQ
What's the safe attachment size for most email providers?
Aim for under 10 MB total per email. Under 5 MB is even safer because some corporate Exchange servers and spam filters get pickier. Gmail's official limit is 25 MB but bulky attachments slow delivery and trigger more spam scoring.
Should I use ZIP to compress further?
Not for images. JPG and HEIC are already compressed — zipping them saves 1–3% at best, and forces the recipient to unzip. Send them as-is or as a single PDF.
Can I batch-compress 20 photos at once?
Yes — drop them all together and the converter applies the same quality setting to each. Download them one by one or look for a 'Download all' option.
Should I resize dimensions or just lower quality?
Both, in that order. A 4032×3024 phone photo doesn't gain much by being shown at full size in an email — resize to 1920px wide first, then drop quality to 75%. You'll get a 90%+ size reduction with no visible loss for normal viewing.