Image Resizer

Resize PNG, JPG and WebP images by pixels with optional aspect-lock. 100% in your browser — files never uploaded. Export as PNG, JPG or WebP at the size you need.

100% in your browser — files never uploaded.
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    How to use the Image Resizer

    1. 1
      Drop an image
      PNG, JPG, WebP — drop the file or pick from your device. The original width and height appear next to the controls.
    2. 2
      Set the target size
      Type the target width or height in pixels. Aspect-lock is on by default — the other dimension follows automatically.
    3. 3
      Pick output format + quality
      Stay in PNG for lossless, switch to JPG or WebP for smaller files. JPEG quality is configurable; PNG is lossless.
    4. 4
      Click Resize, then Download
      Resizing happens in your browser via the Canvas API. Right-click the result to save, or hit the Download button.

    What does resizing actually do?

    Resizing an image changes its pixel dimensions. Making it smaller (downscaling) reduces detail and file size — useful for web pages, social posts and emails where bandwidth matters. Making it larger (upscaling) interpolates new pixels from existing ones; the result rarely looks sharper because no new detail is invented.

    This tool uses the browser's Canvas API, which applies bilinear-or-similar resampling under the hood. For most photos and screenshots that's perceptually fine. For very large upscales or print-grade detail recovery, a dedicated AI upscaler is the right tool — Postcrest's AI Image Upscaler does face-aware, text-aware 4× upscale with detail reconstruction.

    Output format matters: PNG is lossless and supports transparency but produces large files. JPG drops perceptually unimportant detail to land at 70-90% smaller files; no transparency. WebP usually beats both at the same visual quality and supports transparency — modern browsers and platforms accept it.

    Frequently asked questions

    Is this tool really free?
    Yes — free forever, no signup, no watermarks, no per-file limits.
    Are files uploaded?
    No. Everything runs in your browser via the Canvas API. Nothing is sent to Postcrest's servers or any third party.
    Does it work for batches?
    This tool handles one image at a time so you can preview each result. For bulk resizing, use the Bulk Image Resizer tool from the index.
    Will it upscale my image to higher resolution?
    Yes — but the Canvas resampler can't invent detail. For real detail recovery (faces, text), use Postcrest's AI Image Upscaler.
    What's the maximum supported size?
    Limited by your device's memory. Most modern devices comfortably handle 8-megapixel inputs; outputs up to 4K are routine.
    Can I use the resized image commercially?
    Yes — it's your image, just at a different size. You keep all rights.
    Does it preserve transparency?
    Only if you export to PNG or WebP. JPG doesn't support transparency, so the alpha channel is composited onto white.
    Mobile-friendly?
    Yes. iOS Safari and Android Chrome are supported. Very large images may hit memory limits on phones.

    Need more than free tools? Get Postcrest's full AI image suite.

    AI background removal, AI upscaling, AI image editor and AI photoshoot — every leading model in one workspace.

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    Every leading model — Flux, Nano Banana, Seedream, GPT-Image, SDXL.
    AI Image Editor
    Inpaint, outpaint, object removal — describe the edit, AI applies it.
    AI Background Remover
    Pixel-perfect cutouts in seconds — transparent PNG or any new scene.
    AI Image Upscaler
    Upscale to 4K, face-aware, print-ready, watermark-free.
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