Resize Images Online — Bulk Resize Without Uploading

Resize images by longest edge, exact dimensions or percentage, with letterbox or stretch fitting.

Bringing a folder of camera originals down to a sensible size is a single intent applied to many files, so one setting governs the whole queue here. Choose a longest-edge limit, an exact frame, or a percentage, and every queued picture is resampled to match and re-encoded in the format you select.

How to resize images

  1. Drop your images onto the upload zone or click it to choose them; every file is analysed so its current dimensions show in the queue.
  2. Choose a mode: Longest edge (1920 px by default), Exact width × height with an optional letterbox fit, or Percentage from 1 to 400.
  3. Pick the output format — JPEG, PNG, WebP or AVIF — and set its quality or lossless option.
  4. Press Process to resample the queue, then download each file from its row or grab all of them with Download all as ZIP.

Three ways of saying how big

Longest edge caps whichever side is larger and lets the other follow, which handles portrait and landscape shots in one setting — exactly what you want when the real requirement is a ceiling rather than a shape. Percentage scales both sides by the same proportion and is the natural choice for halving a set of screenshots.

Exact width and height names a frame outright. Fit inside letterboxes the picture within that frame and centres it; turning that off stretches the picture to fill the frame, distorting it deliberately for the occasional display that demands precise dimensions.

Resizer formats, batch size and privacy

Large reductions are done in steps

Resampling a four-thousand-pixel photograph straight down to four hundred in one pass makes fine detail alias badly: repeating textures crawl and thin lines break up. The standard remedy is to halve repeatedly until the source is within twice the target, then perform one final resample, and that is what happens automatically here.

The intermediate steps are invisible in the result; what you notice is their absence — an edge that stays clean and a pattern that stays a pattern instead of turning into moiré.

Letterbox padding has to be some colour

When Fit inside leaves margins, those margins are transparent for PNG, WebP and AVIF, which all carry an alpha channel. JPEG does not, so its margins are filled white instead — left as nothing, they would encode as solid black bars, which is rarely what anyone wanted.

The note under the format controls states which behaviour applies to your current selection, so the choice of output codec and the appearance of the padding are never separated by a surprise.

Common image sizes to resize to

Questions people ask about Image Resizer

Can I enlarge a small image?
The controls allow it, but interpolation only estimates values between pixels that already exist. The output is a bigger and softer version of the input rather than a more detailed one, which is worth doing only when some system demands a minimum size.
Does every file in the queue get the same setting?
Yes, and that is intentional — a size limit is a property of where the images are going, not of each individual picture. Resolving each one against its own dimensions means portrait and landscape shots both respect the same rule.
Which output format should I pick?
WebP is the usual best balance of size and compatibility for the web today. Choose PNG when transparency must survive, AVIF when the smallest possible file matters more than older browser support, and JPEG when a consumer of the file insists on it.
Are the originals modified?
Never. Files are read into memory, resampled and written out as new downloads; nothing on your disk is touched or replaced. The queue rows show the before and after dimensions side by side so the change is explicit before you save anything.
Does resizing an image reduce its quality?
Shrinking always removes pixels, but stepped downscaling keeps edges and textures clean, and the result is then re-encoded in your chosen format. Choose PNG or lossless WebP if you want no additional compression loss on top of the resize.
Can I resize multiple images at once and download them as a ZIP?
Yes. Queue up to 40 images on the free tier, apply one size setting, and press Process; when more than one file finishes, a Download all as ZIP button appears next to the per-row download links.
Are my images uploaded to resize them?
No. Each image is decoded, resampled and re-encoded by Web Workers running in your browser tab, and the downloads are created locally from memory, so no picture or filename leaves your device during the process.
Can I resize an image to a specific file size in KB?
Not directly, because this tool sets pixel dimensions rather than a byte target. Resize to the dimensions you need here, then open the result in the Image Compressor and lower the quality until the estimated size fits.

Related tools on BrakeTools

Content reviewed 2026-09-27.