How to Resize an Image

Resizing is the most useful thing you can do to an image and the most misunderstood. Drop a file into Resize Image, set your target dimensions, and download. The interesting part is knowing what to set them to.

Resize versus compress — they're not the same

These get conflated constantly. Resizing changes the pixel dimensions: a 4000×3000 photo becomes 800×600. Compressing keeps the dimensions and encodes the same picture with fewer bytes.

Both shrink the file, but resizing is usually the bigger and better lever. Halving the width and height quarters the pixel count — a huge reduction before compression even starts. If a photo is far larger than it will ever be displayed, resizing costs you nothing visible and saves enormously. Compressing an oversized image, by contrast, means degrading detail you're then not even showing.

The best results come from doing both, in order: resize first, then compress. Our guide on hitting an exact size limit covers why that order matters so much.

Keep the aspect ratio

Aspect ratio is the relationship between width and height. Change one without the other and people look stretched or squashed. Unless you have a specific reason, keep the ratio locked and set only one dimension — the other follows automatically.

When you genuinely need a different shape, crop, don't stretch. Cropping removes pixels from the edges and keeps everything else in correct proportion. Crop Image is the right tool, or Crop to Square for the common 1:1 case.

Shrinking works. Enlarging mostly doesn't.

Making an image smaller is straightforward — you're discarding information, and the result looks clean.

Making it bigger is a different story. The detail simply isn't in the file. Enlarging invents new pixels by interpolating between existing ones, which produces a softer, blurrier image, not a sharper one. Doubling a small photo gives you a large blurry photo. If you need a high-resolution image, the answer is to go back to the original source at full size — enlarging is damage control, not a fix.

What size should you actually use?

• Web pages: roughly the display width, doubled for high-DPI screens. An image shown in a 600px column is well served at 1200px.
• Email attachments: 1000–1500px on the long edge is plenty and keeps the message light.
• Upload forms with KB limits: 800–1200px on the long edge, then compress to target.
• Printing: different maths entirely — print needs far more pixels than screens, and our explainer on what DPI actually means covers how to work backwards from a physical size. Don't size a print job by what looks right on a monitor.
• Social media: each platform has its own expected dimensions. Resize for Instagram and Resize for YouTube Thumbnail handle the two most common.

If you'd rather scale by proportion than pick exact numbers, Resize by Percentage is often more intuitive — "half the size" beats doing arithmetic on 4032×3024.

FAQ

Will resizing reduce quality?
Shrinking, essentially no — you're discarding detail you weren't displaying. Enlarging, yes: it softens the image, because the detail isn't there to recover.

Should I resize or compress?
Both, in that order. Resize to the dimensions you actually need, then compress to hit a size target.

How do I resize without stretching?
Keep the aspect ratio locked and set one dimension. To change the shape, crop instead of stretching.