How to resize images without losing quality
Why shrinking is safe and enlarging is not, what the fit modes actually do, and the settings that keep a resized image sharp.
In short
Reducing size is nearly lossless — pixels are averaged down and the result stays crisp. Enlarging cannot add detail and always softens. Resize from the largest original you have, in one step, and keep the aspect ratio locked.
Resizing down and resizing up are not two directions of the same operation. One has a correct answer and the other is guesswork.
Shrinking is safe
When you reduce an image, each output pixel is averaged from the several input pixels it covers. Nothing is invented, and the averaging actually removes noise, so a downscaled photo often looks cleaner than the original at the same display size. This is why you can shrink aggressively without visible cost.
Enlarging cannot work
Going the other way there are more output pixels than input ones, so the extra pixels have to be guessed by interpolating between neighbours. That guess is always smooth, which is exactly why upscaled images look soft. No amount of sharpening puts back detail that was never captured.
The fit modes
| Mode | Behaviour | Use when |
|---|---|---|
| Fit | Whole image inside the box, padding added | Nothing may be cut off |
| Fill | Fills the box, edges cropped away | Filling the frame matters more than the edges |
| Stretch | Distorts to exact dimensions | Almost never — it warps faces and circles |
If you care which part survives rather than letting the centre win by default, crop deliberately first and then resize the result.
Practical rules
- Resize in one step, from the original. Repeated resizes accumulate softening.
- Keep the aspect ratio locked unless you have a specific reason not to.
- Aim for about twice the display size on high-density screens.
- Resize first, then compress. Doing it the other way round means compressing pixels you are about to throw away.
Mistakes worth avoiding
- Resizing a JPEG repeatedly. Each save re-encodes and degrades it further.
- Using Stretch to make an image fit a shape. Crop instead.
- Enlarging to meet a platform's stated minimum. It adds file size and no detail.
Tools used in this guide
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