Aspect ratio is the relationship between an image's width and height. If you change one without the other, the picture stretches or squashes. Keeping the ratio locked preserves the way the scene actually looks.
Why Proportions Matter
Resize by Exact Dimensions (and Stay Proportional)
- Open the Image Resizer and upload your image.
- Choose the "Exact dimensions" mode.
- Enter the width you need, keep "Lock aspect ratio" turned on, and the tool calculates the correct height for you.
- Resize and download.
Resize by Percentage
If you don't have exact pixels in mind, a percentage is easier. Choose 50% or 75% and both dimensions scale together, so the image keeps its original shape. This is perfect for making a picture "half the size" for a webpage.
Shrink File Size Without Distortion
Dimensions aren't the only lever. Choosing JPG or WebP and setting a target maximum file size (like 100 KB) shrinks the bytes while the picture stays proportional. PNG is lossless, so switch to JPG or WebP when you need a much smaller file.