How to reduce image size for email
Modern phones take beautiful, detailed photos, but each one is often 3–5 MB. Attach five or six of them and your email is suddenly too big to send, or takes ages to upload and download. The good news: you can make photos 10–20 times smaller in under a minute, and the person you send them to will hardly see a difference.
Why are photos too big for email?
Most email services limit the total size of the attachments in one message:
- Gmail: 25 MB
- Outlook.com: 20 MB
- Yahoo Mail: 25 MB
- Many company email systems allow only 10 MB
In practice you can attach a bit less than that, because attachments grow by about a third when they are encoded for sending. A 25 MB limit fits roughly 18 MB of files.
The real problem is that phone photos are far bigger than they need to be on a screen. A 12-megapixel photo is about 4000 × 3000 pixels, while most people look at it on a phone or laptop screen that shows a fraction of that.
The quick method: two steps
Step 1: Resize the photo
Reducing the width and height is what saves the most space. Open our free Resize Image tool, add your photos and choose a size:
- Email (800 px) – perfect for viewing on phones and in the email itself
- Website (1200 px) – a good choice if the person may view the photos on a large screen
- Large (1920 px) – full-screen quality, still much smaller than the original
Keep "Do not enlarge smaller images" switched on, so small pictures stay sharp.
Step 2: Compress the photo
Next, open Compress Image, add the resized photos and pick Balanced. This makes the file much smaller with almost no visible change. Use Compare to see the before and after side by side.
Together, these two steps usually turn a 4 MB phone photo into 100–300 KB. That means you can attach dozens of photos to one email instead of five.
Which size should you choose?
- Just to look at on a phone or computer? 800 px is plenty.
- Might they want to zoom in or view full screen? Use 1200–1920 px.
- Will they print the photo? Do not shrink it – send the original, or share a cloud link instead.
Special cases
Screenshots and PNG files
Screenshots are saved as PNG, which can be large. If a screenshot is mostly a photo or has lots of colours, converting it with PNG to JPG often makes it several times smaller. Screenshots with mostly text and flat colours are usually fine as PNG – just compress them.
iPhone photos (HEIC)
iPhones often save photos as HEIC. Many computers and email programs still cannot open HEIC files, so the person receiving them may see an error. Convert them first with HEIC to JPG, then resize and compress as above.
Many photos at once
Our tools handle up to 20 images at a time and let you download them all together as a ZIP file. If you need to send documents such as receipts or forms, you can also turn several photos into one tidy PDF with JPG to PDF.
Tips for the best result
- Always keep the original photos. Send the small copies, keep the big ones.
- Resize first, then compress – this gives the smallest files with the best quality.
- Do not compress the same photo again and again; each round loses a little detail.
- For very large collections, such as a whole holiday album, a shared cloud folder is easier than email.
Frequently asked questions
Will the photos look worse?
On a phone or computer screen, very rarely. Resizing to 800–1200 px and using the Balanced setting removes detail the screen could not show anyway. Use the Compare view if you want to check before downloading.
What is the best image size for email?
For viewing on screens, 800–1200 pixels wide is ideal. Each photo then usually ends up between 100 and 300 KB.
Can I reduce the size without changing the dimensions?
Yes. Use only Compress Image. The file gets smaller, but less so than when you also resize.
Are my photos uploaded to a server?
No. All MagicPicTool tools work inside your browser, so your photos never leave your device. This also makes them fast, even with many files.
Try it now – free, no sign-up, and your files stay on your device.
Open Compress Image