Resizing seems simple, yet it is the most common reason pictures end up soft, pixelated or stretched. The trick is understanding what resizing actually does to the pixels, and following a few rules.
Making an image smaller is safe, making it bigger is not
When you shrink an image, the software merges pixels. Done with a good algorithm, the result looks sharp because you are discarding detail that did not fit on screen anyway.
When you enlarge an image, the software has to invent new pixels in between. It can smooth them nicely, but it cannot create real detail, so enlarged pictures look softer. That is why you should always start from the largest original you have.
Step-by-step: resize an image online
- Open the Image Resizer.
- Add your picture (or a whole batch).
- Choose Pixels and type the new width, or Percentage to scale proportionally.
- Keep Lock aspect ratio switched on so the picture is not stretched.
- Choose the output format and quality, then download.
Keep the aspect ratio
The aspect ratio is the relationship between width and height. If you change only one dimension without the other, the picture looks squashed or stretched. Locking the ratio calculates the second value for you. Not sure what ratio you have? The Aspect Ratio Calculator tells you.
What size do I need?
| Use | Recommended width |
|---|---|
| Website content image | 1200 to 1600 px |
| Full-width hero banner | 1920 px |
| Blog thumbnail | 600 to 800 px |
| 600 to 1000 px | |
| Social media post | See the size guide |
| Print at 300 DPI | Width in inches x 300 |
Resizing many images at once
Use the Bulk Image Resizer. Set the size once, drop in every photo and download a single ZIP.
If you must enlarge
- Enlarge by the smallest factor you can (2x rather than 4x).
- Use the Image Upscaler, which resamples in several steps and sharpens edges afterwards.
- Do not enlarge twice. Scale once from the original.
- Accept that a tiny image will never look great poster-sized.
Common mistakes
- Resizing a compressed JPG and saving again repeatedly. Work from the original each time.
- Changing the ratio and distorting faces.
- Using a low-quality setting and then wondering why it looks blocky. Keep quality around 90 percent when resizing, then compress at the end.
- Forgetting that screens show images at a limited size. Uploading a 6000 px photo for a 600 px slot only slows the page.
After resizing: compress
Once the picture is the right size, run it through the Image Compressor to reduce the file size further without visible loss.
Shrinking is easy, enlarging is not
Making a picture smaller loses nothing you will notice. Making it larger forces software to invent pixels, which is why enlarged images look soft. Know which one you are doing.
Best practice for shrinking
- Resize once, from the original.
- Reduce to the size you will display, or at most twice that for sharp screens.
- Keep the aspect ratio locked, or the picture will stretch.
- After resizing, a light sharpen can restore crispness. See sharpen image.
Best practice for enlarging
- Do not enlarge by more than about 2x if you can avoid it.
- Use the image upscaler, which enlarges and then recovers edge definition.
- Start from the best source you have. A phone photo enlarges far better than a screenshot of a thumbnail.
Batch jobs
If you have a whole folder to shrink, use the bulk image resizer and download everything as a ZIP.
Final step
Resizing changes pixels, but file size depends on compression too. Finish with the image compressor. To understand why print and screen sizes differ, read DPI vs PPI explained.
Frequently asked questions
Why does my image look blurry after resizing?
Enlarging forces the software to invent new pixels, which makes pictures soft. Starting from a larger original and making images smaller keeps them sharp.
What is the best way to resize many photos?
Use a bulk resizer. Set the target width once, drop in all your pictures and download them together as a ZIP.
How do I keep the proportions when resizing?
Lock the aspect ratio so that changing the width automatically calculates the matching height.
Does resizing change the file size?
Yes. Fewer pixels mean a smaller file. Halving the width and height reduces the file size by roughly three quarters.
