Image Resizer

Resizing changes how many pixels an image contains. Shrinking is called downsampling: groups of source pixels are blended into fewer output pixels. Enlarging is upsampling, where new pixels are interpolated between existing ones; it can’t add real detail, so an enlarged image looks softer. File size scales roughly with pixel count, so halving the width and height of a photo cuts its pixels to a quarter and usually its file size by a similar amount.

Pixels mode lets you type a width, a height or both. With aspect-ratio lock on and both values set, the image is scaled to fit inside that box without distortion; with the lock off, it is stretched to exactly those dimensions. Leave one field empty and the other is calculated proportionally. Percent mode scales from 5% to 400%, with one-tap 25%, 50%, 75%, 150% and 200%. Presets mode covers common targets such as an Instagram post (1080 × 1080), Story or Reel (1080 × 1920), YouTube thumbnail (1280 × 720) and 4K (3840 × 2160). Presets produce that exact size, stretching if the source shape differs.

The “Don’t enlarge” option stops small images from being blown up when you batch-resize a mixed folder, which avoids blurry upscales. Resampling uses the browser’s high-quality canvas smoothing, which gives cleaner results than the default nearest or bilinear scaling. You can keep the original format or output JPG, PNG, WebP or AVIF with a quality setting, so a resize and a format change happen in one step.