How to reduce image size for email
Phone photos are often 3 to 8 MB each, so a handful of them can push an email past its size limit. The fix is to make each image smaller before you attach it, usually by lowering the quality a little and capping the width. Here is how to do it in under a minute.
Why email rejects big photos
Gmail lets you attach up to 25 MB per email and Outlook.com up to 20 MB. Go over that and the message is refused, or the files are turned into a cloud link the other person has to open separately.
Modern phone cameras take 12 to 48 megapixel photos. That is far more detail than any screen needs to show a picture, so most of the file size is wasted when the photo is only going to be looked at on a phone or laptop.
Shrink photos in your browser, step by step
- Open the Image Compressor.
- Add your photos. You can add several at once.
- Set the quality to about 70%. The drop in quality is very hard to see at this level.
- Set the maximum width to 1600 to 2000 pixels. This is the biggest saving for phone photos.
- Press Compress and download. Several photos download together as a ZIP file.
The tool shows how much space you saved. If a photo would not get any smaller, it keeps the original rather than making it bigger.
Which settings to use
- For viewing on screen: maximum width 1600 px and quality 70%. A typical phone photo ends up at a few hundred KB.
- For printing: keep the full width and use quality 85% so fine detail survives.
- For screenshots and graphics saved as PNG: the compressor reduces the number of colours, which shrinks them a lot without blurring text. If the PNG is actually a photo, convert it with PNG to JPG instead.
- If you only need a smaller size and not a smaller file, use Resize Image.
iPhone photos in HEIC format
iPhones save photos as HEIC by default, and many email apps and computers cannot open them. Convert them first with HEIC to JPG, then compress the JPG files as above.
Your originals stay as they are
Compressing makes new, smaller copies. The photos on your device are not changed, and because everything runs in your browser, they are never uploaded anywhere.
Why the limit is smaller than you think
Email carries attachments as text, and that encoding adds roughly a third to their size. So ten photos that add up to 18 MB on your phone can arrive as about 24 MB, which is already close to the 25 MB Gmail limit. If a message bounces even though the files looked small enough, this is usually why.
A safe rule is to keep the total of all attachments below about two thirds of the limit. For Gmail that means aiming for 15 MB or less in one message, and for Outlook.com about 13 MB.
A worked example: ten holiday photos
Say you took ten photos on a recent phone and each is about 4 MB, so 40 MB in total. That cannot be sent in one email.
- Add all ten to the Image Compressor.
- Set the maximum width to 1600 pixels and the quality to 70%.
- Compress. Each photo typically drops to somewhere between 200 and 500 KB, depending on how detailed the scene is.
- Check the total shown on screen. Ten photos at that size come to roughly 2 to 5 MB, which sends easily.
The pictures still fill a laptop screen and look sharp on a phone. What you have given up is detail that only shows when you zoom far in or print large.
When you should not shrink the photo
- Sending to a photographer, printer or designer: they need the full-size original. Use a file-sharing link instead of an attachment.
- Legal or insurance claims where detail matters, such as a photo of damage: send the original and a smaller copy for quick viewing.
- Photos you plan to edit further: shrink a copy for sending and keep the original.
On an iPhone, the Mail app can also offer to resize images when you attach them, with choices like Small, Medium, Large and Actual Size. It is a quick option for one or two photos, but the compressor gives you more control and handles many files at once.
Problems and fixes
- The photo is still too big after compressing: lower the maximum width to 1200 pixels. Width has the largest effect on file size.
- Text in a screenshot looks fuzzy: screenshots are usually PNG. Keep the quality high, or send them as PNG without converting to JPG.
- The photo opens sideways: this can happen when a viewer ignores the rotation stored in the file. Open the result before sending, and if it looks wrong, try sending a different copy.
- Your phone photos are HEIC and the other person cannot open them: convert them with HEIC to JPG first.
- You have many photos to send: share a link to an album from your cloud storage rather than attaching everything.
Frequently asked questions
Will compressing make my photos look worse?
At about 70% quality the difference is very hard to see on a screen. Lower settings save more space but can show blocky areas in smooth skies or shadows.
How small should a photo be for email?
Under 1 MB per photo is plenty for viewing on screen. Ten photos at that size fit comfortably under Gmail and Outlook limits.
Are my photos uploaded?
No. The compression runs in your browser, so your photos stay on your device.
Why did my email fail when the photos looked under the limit?
Attachments grow by about a third when they are encoded for email. Keep the total below roughly two thirds of the stated limit.
Can I compress many photos at once?
Yes. Add as many as you like, and when there is more than one they download together as a ZIP file.
Is it better to lower the quality or the width?
Lowering the width saves the most. Reduce quality only a little, to about 70%, because below that the loss starts to show.
Will the other person see a difference?
On a screen, almost never. The difference shows only when someone zooms in very far or prints the photo large.