Compress an image to 1 MB
The editor above is set to a one-megabyte ceiling — it shows as 1024 in the size field, because the field counts kilobytes. Open a photo and CropShrink finds the highest quality whose file still fits, then reports the result to the byte. A megabyte is generous, so for most photos the answer is a quality you cannot tell from the original.
How much a megabyte holds
We measured from the full-resolution original of our sample, a detailed 6720 × 4480 landscape from a full-frame camera, running the editor’s own Lanczos3 resize and size search at seven widths:
| Pixels | Megapixels | WebP quality | JPEG quality | Result |
|---|---|---|---|---|
| 1200 × 800 | 0.96 | 99 | 99 | No visible loss |
| 1600 × 1067 | 1.71 | 99 | 98 | No visible loss |
| 1920 × 1280 | 2.46 | 99 | 96 | No visible loss |
| 2400 × 1600 | 3.84 | 93 | 92 | No visible loss |
| 3000 × 2000 | 6.00 | 88 | 85 | No visible loss |
| 4032 × 2688 | 10.84 | 78 | 66 | Clean; JPEG slightly soft |
| 6720 × 4480 | 30.11 | 35 | 22 | WebP soft; JPEG blocky |
Up to six megapixels a megabyte costs nothing visible. A phone’s full 12-megapixel frame — the 4032 row — still fits as a clean WebP at quality 78, so a phone photo can usually go under 1 MB without resizing. Only a large camera file, like the 30-megapixel original at the bottom, needs fewer pixels.
When the photo is from a big camera
Given the whole 30-megapixel original as JPEG, the search fits it at quality 22, which shows blocks in the sky and the trees. Below quality 30 the editor says the result will look rough and offers a size worth having instead: here, 4180 × 2787. At that size the search landed on quality 62 and 1,027,668 bytes. The offer is worked out from the file encoded at quality 50 during the first search, scaled so that the next one lands close to it, and nothing is resized until you press the button.
As WebP the same original fits at quality 35. That is above the threshold, so no offer appears, but the advice still applies: about 4000 px wide is where a megabyte stops being a compromise.
Photos for email
A megabyte per photo is the usual advice for email, for reasons that are worth knowing:
- Attachments grow in transit. Email carries files as text, using an encoding called Base64 that makes them about a third larger. Ten 1 MB photos travel as nearly 14 MB.
- Mailboxes have limits. Gmail, for example, accepts up to 25 MB of attachments in one message. Phone originals of 4 or 5 MB fill that with five or six photos; 1 MB versions leave room for several times as many.
- The reader is often on a phone. A 4000-pixel photo is already larger than any phone screen; nobody receiving it will see the difference a 10 MB original would make.
If the recipient needs to print large or edit the photo, send the original through a file-sharing link instead of shrinking it.
Which megabyte?
Here a megabyte is 1,024 × 1,024 = 1,048,576 bytes. Windows counts the same way. macOS Finder, and many upload forms, count in thousands, so to them a megabyte is 1,000,000 bytes and a file CropShrink calls 1.00 MB shows as 1.05 MB. If a form must accept the file whichever way it counts, set the target to 976: that is 999,424 bytes. Each result’s exact byte count appears under the quality slider, so you can check it against the form’s wording.
Questions about 1 MB limits
Can a phone photo be under 1 MB without resizing?
Usually, yes. A 12-megapixel, 4032-pixel-wide photo fits 1 MB at quality 78 as WebP or 66 as JPEG, both clean. Only much larger camera files need to be made smaller.
What should I type for 1 MB?
1024, because the size field is in kilobytes; this page opens with it already set. Type 976 if the form counts a megabyte as 1,000,000 bytes.
Why does my 1 MB file show as 1.05 MB on a Mac?
Finder counts a megabyte as 1,000,000 bytes, while CropShrink and Windows count 1,048,576. It is the same file. Set the target to 976 if the difference matters.
Is anything uploaded?
No. The photo is decoded, resized and encoded in your browser and saved from there. The privacy policy shows how to check that no request carries it.
Other limits
Tighter limits have their own measurements: 500 KB, 200 KB and 100 KB. Any other figure can be typed into the size field.
More image tools
Every one of these is the same editor, opened for a different job — and all of them run on your device.
- Compress an imageShrink a photo for the web, an email or an upload form.
- Compress to 500 KBKeep a camera photo full-screen sharp under 500 KB.
- Resize an imageChange the pixel dimensions with Lanczos3, Catmull-Rom or Mitchell.
- JPG to AVIFRoughly halve a photo, converted on your device.
- Remove EXIF dataStrip the GPS location, camera and serial number from a photo.
Or start from the full editor, which does all of it at once.