Last updated: October 15, 2026
The short answer
When we Make an image smaller, image normally keeps it qaulity as long as its done properly. However, increasing image dimensions is different: tools can not add details, so large enlargement always reduces some sharpness.
Why quality of image changes after resizing
A digital image is a grid of tiny colored squares called pixels. When you shrink an image, the tool combines pixels and the picture retains its sharpnessp at its new. When we enlarge an image, the tool has to invent new pixels by checking pixels around them. The more you enlarge, the more guessing happens and image loses its quality.
How to resize an image, step by step guide
- Open the Image Resizer.
- Click the button in upload area and choose your photo from your file in your browser, or drag it in. Your photo stays on your device.
- Type the new width or height in pixels in window where you uploaded image. Leave Keep proportions ticked, so the other side updates by itself autommatically and the photo is not stretched.
- Choose a format which suites your requirment. JPG works well for photos. PNG is better for screenshots, logos or anything with a transparent background.
- Set the quality to High, then click Resize image.
- Compare image in the Before and After panels, then click download to get the result.
Tips for the best result
- Keep your original image. Always resize a copy, so you can start again if you need a different size.
- For good results resize image from the original, not from a resized copy. Repeated edits stack up small losses, especially with JPG files.
- Avoid big enlargements. If you need a larger image, start from the biggest version of image which you have.
- Keep the proportions locked unless you want to crop. To change the shape on purpose, use the Image Cropper.
- Match what you need. If a website asks for a specific size in pixels, enter exactly that width and height.
Common questions
Does resizing change the image size?
Usually, yes. An image or photo with fewer pixels normally makes a smaller file, although the change is not exactly proportional. If you need a specific file size, see our guide on compressing an image to 100 KB.
Why does my resized photo look stretched?
The width and height were changed by different amounts. Turn on Keep proportions, and change only one side, tool will automatically adjust remaining dimensions.
Should I use JPG or PNG?
Choose JPG for images where more details are required and PNG for graphics and transparency. We explain the difference in PNG vs JPG vs WebP.