Resize Images Online

How to resize an image

To resize an image, drop your photos onto the panel above, type the width you want, and press Resize. With the link icon closed the height follows automatically along the image's own proportions, so nothing stretches.

Two controls decide everything. Resize by chooses whether you are naming an exact size in Pixels or scaling each image relative to itself in Percent — pixels for “every thumbnail must be 400 wide”, percent when the originals vary in size and each should shrink by the same proportion. The width presets cover the sizes that come up most: 640 for email, 1280 for web, 1920 for Full HD, and 3840 for 4K.

The link button between the width and height fields is the one worth understanding, because it is what protects you from a stretched photo. Closed, either measurement follows the other along the original ratio. Open it only when you deliberately want a different shape, and if the shape you need differs from the photo's, crop to that ratio first — that way you decide what gets cut rather than squashing the whole frame.

How to reduce image size in KB

To reduce image size in KB rather than in pixels, use the compressor's target-size mode — file size is set by compression, not by dimensions.

The distinction catches people out because both tasks get called resizing. Width and height describe how many pixels the image contains; kilobytes describe how many bytes those pixels take to store, and two images with identical dimensions can differ tenfold in file size depending on their content. So a form demanding “under 50 KB” is asking a compression question.

Resize here first only when the form *also* specifies dimensions, then compress the result to the limit. Dedicated pages open with the budget already set: 20 KB, 50 KB, 100 KB, and 200 KB.

Resize a photo for Instagram and social media

Switch to Pixels mode and enter the placement's dimensions — 1080 × 1080 for an Instagram square post, 1080 × 1920 for a story or Reel.

Check the shape before you resize. If your photo's proportions differ from the placement's, crop to the ratio first, because otherwise the platform crops it for you and it takes the middle of the frame whether or not that is where the subject is.

Passport and ID photos work differently and are not worth doing by hand here: the passport photo maker locks each document's shape and writes the exact pixel dimensions portals expect at 300 DPI.

Resize multiple images at once

Drop a whole folder and every image is resized in one pass — the button reads Resize N images — then downloads together as a single ZIP.

Which mode you want depends on whether the originals match. Pixels mode puts the entire batch on the same dimensions, which is what you want for uniform thumbnails or catalogue shots. Percent mode scales each image relative to its own size, which is better when the originals vary and a fixed width would crop some and stretch others.

How to increase image size without losing quality

To increase image size, use Upscale rather than this tool — enlarging needs a sharpening pass that plain resizing does not apply.

No tool can invent detail that was never captured. Enlarging spreads the pixels you have across a larger grid, and past roughly 200% the result softens no matter what software you use. What a good enlargement does is hide that softening: the upscaler steps the image up and then restores edge contrast, which reads as sharp where a plain resize reads as blurry.

Downscaling is the direction that can genuinely be lossless to the eye, and it is worth knowing why this tool does it well. A naive single-step reduction samples the original too sparsely and produces shimmering edges and moiré patterns in fabric and brickwork. This one steps down in halves and smooths only the final step, the same approach professional editors take, so even large reductions stay clean. Two habits help further: always resize from the largest original you have rather than an already-shrunk copy, and resize before you compress, since halving both dimensions removes about 75% of the data before compression starts.

What size should an image be?

Match the largest size the image will ever be displayed at, then stop. Serving a 4000 px photo into an 800 px slot costs bandwidth and adds no visible detail.