Guide
How to Reduce an Image for Email and the Web
Last updated October 5, 2026
A phone photo is often 2 to 6 MB and 4000 pixels wide, far more than an email, a web page or a form needs. The quickest way to shrink it is not a quality slider. Pixels cost bytes, so removing pixels you will never see saves the most, and compression is the finishing step. This guide shows the order that works, with numbers from one test photo.
Step 1: find out what you have and what you need
Read the picture's pixel size and file size with the Image Dimensions Checker, which runs in your browser and uploads nothing. Then find the size the destination actually needs. A page that shows an image 800 pixels wide gains nothing from a 4000-pixel file, and many forms state a maximum width or file size. If a form gives only a file size, work backwards in steps: resize, check, resize again if needed. Provider limits differ, so look up the limit for your own email or upload form.
Step 2: resize before you compress
Use the Image Resizer to set the width you need, with the aspect ratio locked. This is where most of the saving comes from. We ran a generated 4000 × 3000 photo-like JPG of 2.0 MB through the tools in different orders:
| What we did | Result | File size |
|---|---|---|
| Compress only (JPG Compressor) | 4000 × 3000 | 618 KB |
| Resize to 1600 px wide | 1600 × 1200 | 92 KB |
| Resize to 1600, then compress | 1600 × 1200 | 82 KB |
| Resize to 1200 px wide | 1200 × 900 | 49 KB |
| Resize to 1200, then compress | 1200 × 900 | 43 KB |
| Resize to 1200, then convert to WebP | 1200 × 900 | 17 KB |
Generated locally; not a benchmark; not a guaranteed result. The test photo is smooth and compresses well, so real photos will end up larger. The order is what matters: compression alone left 618 KB, while resizing alone left 92 KB. Once the picture was resized, compressing it saved only about 10% more.
Step 3: compress once
The Image Compressor re-saves a JPG or WebP at quality 75 and a PNG without loss. Do it once. Each further pass on a JPG or WebP loses a little more detail and saves less. If a PNG gets larger after compression, that is normal: PNG is lossless here, and a PNG already saved by another program can come back bigger. Convert it instead (step 4).
Step 4: pick the right format
Photographs belong in JPG or WebP. Screenshots, text and logos are smaller as PNG or WebP than as JPG. Our generated 1200 × 800 photo was 1.55 MB as a PNG and 80 KB as a JPG. See JPG vs PNG vs WebP for the full comparison. For email, a JPG is the safe choice because everything opens it. WebP is smaller but not every program opens it.
Step 5: check the result before you send it
- Open it at the size it will be shown, not zoomed in.
- Check the picture is the right way up. Phone photos can carry a rotation flag; the resizer and compressor apply it to the pixels, so the result is upright. If a photo ever looks sideways, use the Image Rotator.
- Remember that re-saving drops location and camera data. If you only want that removed, the Image Metadata Remover does it without re-encoding.
Common mistakes
- Compressing again and again to reach a size: lower the pixel size instead.
- Making a PNG of a photograph: it will be many times larger than a JPG.
- Enlarging a small image to "improve" it: this adds pixels but no detail, and the file gets bigger.
- Cropping when you meant to resize: cropping removes parts of the frame, which is right for framing but a poor way to reduce size.