How to Resize Images Without Stretching Them

Understand aspect ratio, how to keep proportions when changing width and height, and which file format to choose.

Stretched images happen when width and height are changed by different proportions. The fix is to keep the aspect ratio, which is width divided by height.

The maths of aspect ratio

A 1920 × 1080 image has a ratio of about 1.78 (16:9). To resize it to 800 px wide, the new height is 1080 × 800 ÷ 1920 = 450 px. The Image Resizer does this automatically when Keep aspect ratio is ticked.

Steps

1. Choose an image from your device. It is processed in your browser.
2. Enter a new width or height. The other value updates to keep proportions.
3. Pick an output format and select Resize image.
4. Check the preview and file size, then download.

Choosing a format

• JPEG: good for photos, smaller files, no transparency.
• PNG: good for graphics and transparency, often larger.
• WebP: usually smaller than both, supported by modern browsers.

Tips

• Avoid enlarging small images beyond their original size, as they will look soft.
• Keep a copy of the original file.
• If you need a different shape, crop first and then resize.