Use this image resizer when a photo is too big for a website, a form upload or a social post. Set the new size in pixels or as a percentage, preview it and download. The image never leaves your browser.
How to use the image resizer
- Choose one image in JPG, PNG or WebP format.
- Pick the unit: pixels (px) or a percentage (%) of the original size.
- Enter the new width or height. With the keep aspect ratio lock on, the other value updates by itself so the picture is not stretched. Turn the lock off only when you need an exact size, such as 600 × 600.
- Choose the output format: JPEG, PNG or WebP. For JPEG and WebP, set the quality as well.
- Check the preview, the new dimensions and the file size, then download the resized image.
Pixels, percentages and aspect ratio
A digital photo is a grid of pixels. A picture that is 4000 × 3000 has 4,000 columns and 3,000 rows, which is 12 million pixels. Resizing changes the size of that grid. Setting 50% halves both sides, so 4000 × 3000 becomes 2000 × 1500, and the image now has only a quarter of the pixels.
The aspect ratio is the ratio of width to height. A 4000 × 3000 photo is 4:3, and a 1920 × 1080 screenshot is 16:9. If you change the width and height by different amounts, faces and circles look squashed or stretched. That is why the lock is on by default.
| Original | Setting | Result (lock on) |
|---|---|---|
| 4000 × 3000 | Width 1600 px | 1600 × 1200 |
| 4000 × 3000 | 50% | 2000 × 1500 |
| 1080 × 1350 | Height 675 px | 540 × 675 |
| 1920 × 1080 | Width 1280 px | 1280 × 720 |
Tip: To get a square image from a non-square photo without stretching it, you would need to crop it. This tool only resizes, so turning the lock off will distort the picture.
Making images bigger vs smaller
Shrinking an image works very well: the browser averages neighbouring pixels and the result looks sharp. Making an image larger is different. The resizer cannot invent detail that was never captured, so an enlarged photo looks soft or blurry. If you need a bigger image, go back to a larger original if you have one.
Which output format to choose
- JPEG for photos that must open everywhere, such as uploads to government or exam portals that ask for a JPG.
- PNG for screenshots, logos and images with transparency. It is lossless, so the quality setting does not apply, and photos saved as PNG are often large.
- WebP for websites. It supports both transparency and lossy compression, and all major browsers can show it.
For more detail on these formats, see MDN’s image file type guide.
Choosing the right size for the web
For a web page, resize images to roughly the largest size they will be shown at, and about twice that if you want them to look crisp on high-density phone screens. A full-width banner rarely needs more than 2000 pixels across, and a thumbnail in a card may only need 400. After resizing, you can shrink the file further with our image compressor. Our guide to image optimization for the web explains how resizing fits with formats and lazy loading.
Learn more
- Image Optimisation for the Web: Formats, Sizes and Lazy Loading
- HTML Images
- CSS Responsive Design
- Image Compressor
- JPG to PDF Converter
Frequently asked questions
Is my photo uploaded to a server?
No. The resizing happens inside your browser using your device’s own processing, and the download is created locally.
Why did the file size go up after resizing?
This usually happens when you save a photo as PNG, which is lossless and stores every pixel exactly, or when you set a high JPEG or WebP quality. Choose JPEG or WebP and lower the quality a little to get a smaller file.
How do I resize an image to an exact size like 300 × 300?
Turn off the keep aspect ratio lock and enter both values. If the original is not square, the picture will be stretched, so it is better to start from a square image.
Does resizing change the DPI for printing?
Printing depends on the number of pixels and the print size. A 1200-pixel-wide image printed 4 inches wide gives 300 pixels per inch. Fewer pixels means a smaller sharp print, whatever DPI value is written in the file.