Image Resizer

How the numbers are worked out

With "Lock aspect ratio" on (the default), the width is authoritative when you give both numbers: the height is recalculated from it, whatever you typed. A 1200 × 800 photo with a requested 600 × 600 comes out at 600 × 400. If you give only a height, the width follows from that instead. Unlock the ratio and both fields are required and used exactly as typed, so 600 × 600 really produces a square, and the picture is squashed to fit. Either way, nothing is cropped: the whole picture is scaled.

What happens to the file

The picture is decoded, scaled and saved again in its own format. JPG and WebP are written at quality 85 and PNG is written losslessly, so a JPG that was saved at a lower quality will not get any worse beyond the normal cost of one more JPG save, and it will not get better either. PNG transparency is kept. Camera data such as EXIF and GPS is not copied to the result, and a JPG that carried a rotation flag is turned upright first, so a phone photo that looked upright before still does.

What a resize saves

Pixels are what cost bytes, so reducing the dimensions usually saves far more than any quality setting. These results come from running this tool on a generated 4000 × 3000 photo-like JPG (2.0 MB):

Generated locally; not a benchmark; not a guaranteed result. The generated picture is smooth and has little fine detail, so a real camera photo will not shrink this much. What carries over is the direction: halving each side leaves a quarter of the pixels.

Enlarging

You can set a size larger than the original, up to the limits below. It does not add detail. A generated 1200 × 800 JPG enlarged to 2400 × 1600 grew from 117 KB to 246 KB and looked the same, only bigger and softer. Enlarge only when a form insists on a minimum size, and expect the picture to look no sharper than the original.

Limits

The source and the result must each be at most 12,000 pixels on a side and 40 megapixels, and the upload at most 20 MB. The limit applies to the size you ask for: a 12,001 px width and a 7000 × 7000 request (49 megapixels, although neither side is over 12,000) were both refused with "The image dimensions are larger than the allowed limit."

When another tool fits better

To cut part of the frame away instead of scaling everything, use the Image Cropper. To shrink the file without changing the pixel size, use the Image Compressor. For a step-by-step approach to email and web sizes, see the guide how to reduce an image for email and the web.

Accepts JPG, PNG and WebP, identified by their contents rather than the extension. The result is in the same format. Limits: 20 MB per file, 12,000 px per side and 40 megapixels, applied to the source and to the size you request. Animated WebP and other formats such as GIF or BMP are not accepted.

1. Choose a JPG, PNG or WebP file (up to 20 MB).
2. Type a width, a height, or both. Leave "Lock aspect ratio" ticked to keep the picture's proportions.
3. Click "Resize Image" and download the result. It is named after your file with "-resized" added.
4. Check the new dimensions, for example with the Image Dimensions Checker, before you upload it somewhere.

• Bringing a camera photo down to the pixel width a website or marketplace listing asks for
• Making a large photo small enough to email before compressing it
• Producing a thumbnail of an exact width
• Meeting a form's stated pixel size, for example 600 × 600, when distortion does not matter

Pixel values only: there is no percentage mode, no preset sizes and no way to aim for a file size in kilobytes. JPG and WebP are saved at a fixed quality of 85. Enlarging does not add detail. Unlocking the aspect ratio can distort the picture. Camera data (EXIF, GPS) is dropped from the result. One file is resized at a time.