Resize by pixels or by percentage
By pixels is for when a website, form or social network asks for a specific size. Type a width, leave the height empty, and the height is calculated to keep the original shape. By percentage is quicker when you just want the photo smaller: 50% halves both the width and the height, which leaves a quarter of the pixels.
Keeping proportions versus cropping
Every image has an aspect ratio, the relationship between its width and height. A phone photo is usually 4:3, a widescreen video frame 16:9, and an Instagram post 1:1. If you force a 4:3 photo into a 1:1 square, something has to give:
- Keep proportions on: the image keeps its shape, and only the width (or height) you typed is guaranteed.
- Keep proportions off with both sides set: the image is scaled until it fills the frame, and the overflow is trimmed equally from both sides. Nothing is stretched or squashed.
Common image sizes
| Where it's used | Size (px) | Ratio |
|---|---|---|
| Instagram square post | 1080 × 1080 | 1:1 |
| Instagram portrait post | 1080 × 1350 | 4:5 |
| Instagram / TikTok story | 1080 × 1920 | 9:16 |
| YouTube thumbnail | 1280 × 720 | 16:9 |
| Facebook / LinkedIn link image | 1200 × 630 | 1.91:1 |
| Full HD wallpaper | 1920 × 1080 | 16:9 |
Platforms update their recommendations from time to time, but these sizes have been standard for years and display well everywhere.
Will resizing reduce quality?
Making an image smaller keeps it sharp, because you're throwing away pixels you didn't need. Making an image bigger can't add real detail: the browser fills the gaps by blending neighbouring pixels, so an enlarged photo looks softer. As a rule, avoid going above 150–200% of the original size.
Resizing versus compressing
Resizing changes the dimensions; compressing changes how efficiently those pixels are stored. Both reduce file size, and they work best together: resize first to the size you'll actually display, then use the image compressor to bring the file size down further.
Frequently asked questions
How do I resize an image without losing quality?
Make it smaller rather than bigger, keep the proportions locked, and save it at high quality. This resizer saves at 92% quality, which keeps photos sharp.
How do I resize a photo for Instagram?
Click the Instagram square preset for 1080 × 1080, or the portrait preset for 1080 × 1350. The photo fills the frame and is centre-cropped so nothing is stretched.
How do I make an image a specific size in KB?
Resizing reduces the number of pixels, which shrinks the file. For an exact file-size limit, resize first and then use the Image Compressor to lower the quality until it fits.
Can I resize multiple images at once?
Yes. Drop several images and they are all resized with the same settings. Download them one by one or all together.
Are my photos uploaded?
No. Resizing happens in your browser, and your photos never leave your device.
Last updated October 2026 · More image tools