How to resize an image
Upload an image and choose Pixels or Percentage. With Pixels, type a new width or height. Keep aspect ratio is on by default, so the other side updates to match and nothing gets stretched. With Percentage, drag the slider between 5 and 200 percent to scale both sides at once.
The panel shows the original and new dimensions and file sizes. Use the compare slider to check sharpness, then download. JPG, PNG and WebP files stay in their own format. HEIC, TIFF, BMP and GIF uploads are saved as JPG, or as PNG when they have transparency.
Pixels, percentage and aspect ratio
Pixels are the right choice when a website, form or template asks for a specific size, such as 1200 pixels wide. Percentage is quicker when you just want everything smaller, for example 50 percent to halve each side. Halving both sides leaves a quarter of the pixels, which usually makes the file much smaller too.
Aspect ratio is the relationship between width and height, like 4:3 or 16:9. Keeping it locked avoids squashed faces and stretched logos. To change the shape, crop the image instead with the Image Cropper, or use the Social Media Image Resizer, which crops to fit.
Can you make an image bigger?
Yes, up to 200 percent or 10,000 pixels per side. The tool uses Lanczos resampling, which keeps edges as clean as possible. But enlarging can't add detail that the original never captured, so a small photo scaled up will look soft. Shrinking always works well, and it is the main reason people resize: smaller dimensions mean faster uploads and lighter web pages.