How to use this image resizer
- Add your images to the dropzone, or press Browse files to select them.
- Type the width you want. With Keep aspect ratio ticked, the height follows automatically.
- Untick the lock only if you deliberately want to stretch the image to fixed dimensions.
- Press Resize images and wait for the batch to finish.
- Check the new dimensions listed with each result, then download individually or as a ZIP.
What this resizer offers
- Fills in the original dimensions automatically so you can see what you are changing.
- Locks the aspect ratio by default, which prevents the stretched look almost nobody wants.
- Applies one set of dimensions across a whole batch, fitting each image inside them.
- Uses high-quality smoothing when downscaling, so edges stay clean rather than jagged.
- Shows the final pixel size and the file size change for every image.
- Keeps PNG transparency intact and never adds a watermark.
Resizing is the most effective saving there is
People reach for a compressor when an image is too heavy, but dimensions almost always matter more. Pixel count scales with the square of the dimensions: an image at half the width and half the height contains a quarter of the pixels. That reduction happens before any compression is applied, and no quality setting can compete with it.
A typical phone photograph is around 4000 pixels wide. A blog post shows it at 800. Serving the original means sending twenty-five times more data than the visitor's screen can use. Resizing to the size it will actually be displayed at is not a compromise. It is removing waste.
Sizes worth knowing
- 1200 px wide: a safe maximum for blog and article images on most layouts.
- 1080 × 1080: the standard square for social posts, with 1080 × 1350 for portrait.
- 1920 × 1080: full-screen banners and presentation backgrounds.
- 600 px wide: email newsletters, where wider images break on mobile clients.
- 512 × 512 or 1024 × 1024: app icons, avatars and marketplace thumbnails.
Why the aspect ratio lock is on by default
Aspect ratio is the relationship between width and height. Change one without the other and the picture distorts, faces widen, circles become ovals, and text leans. It is instantly recognisable and almost never intentional.
With the lock enabled, entering a width computes the matching height for you. Entering both values makes the tool fit the image inside that box while keeping its proportions, so nothing is stretched. Untick the lock only when you genuinely need fixed dimensions and have accepted the distortion, such as filling a background slot where the subject does not matter. To work out proportional dimensions before you start, the aspect ratio calculator does the arithmetic.
Downscaling is safe, upscaling is not
Making an image smaller is a well-behaved operation. The browser averages groups of pixels into fewer pixels using high-quality smoothing, and the result is clean. Some images benefit from a light sharpen afterwards, but most look fine as they are.
Making an image larger is a different matter. The extra pixels have to be invented by interpolating between the ones that exist, so a 400-pixel image enlarged to 1600 is not sharper. It is the same amount of detail spread across more pixels, and it looks soft. If you need a large version of something small, go back to the original source, or if the artwork is vector, export it at the size you need with the SVG converter, which redraws rather than interpolates.
Resize first, then compress
The two operations stack. Resize a 6 MB photograph to 1200 pixels and it might land at 700 KB. Run that through the image compressor at 80 per cent and it becomes perhaps 140 KB, with no visible difference at its display size. Doing it in the other order wastes effort, because you compress detail you are about to throw away.
All of it happens locally. Your images are decoded, redrawn at the new size and re-encoded inside this browser tab, so nothing is uploaded and no server holds a copy of your work.