Resize images without distortion

An image’s aspect ratio is its width divided by its height. A 1600 × 900 image has a 16:9 ratio. Resizing it proportionally changes both dimensions by the same scale factor, so the image keeps its shape.

Use the same scale for width and height

To reduce a 1600 × 900 image to half size, multiply each dimension by 0.5. The result is 800 × 450. To calculate a new height from a chosen width, divide the original height by the original width, then multiply that ratio by the new width. For example, 900 ÷ 1600 × 1200 gives a height of 675 pixels.

When you do not want to calculate the second dimension yourself, turn on the aspect-ratio lock in the image resizer. It updates the other dimension as you edit width or height.

When should you unlock the dimensions?

Unlocking the aspect ratio stretches or squashes the original content to fit the dimensions you enter. That can be useful for a deliberate distortion effect, but it usually changes the apparent shape of people, objects, and circles. If the output must be exactly square or portrait, cropping is usually the better choice.

Resize, crop, or both?

• Resize proportionally when you need the same composition at a different pixel size.
• Crop when you need a new aspect ratio and want to keep subjects at their original proportions.
• Resize after cropping when a service or print workflow asks for exact pixel dimensions.

A preset dimension does not automatically match every source ratio. If the target ratio differs, proportional resizing cannot fill both requested dimensions without empty space or distortion. Crop first or choose another output size.

Choose useful dimensions

Start from the size needed where the image will be displayed or printed. A very large export can take more memory and storage without looking different at its display size. A small export enlarged later may look soft because it contains fewer pixels. Keep the original so you can make another size if your needs change.