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PNGful

Compress an image to an exact file size

Need a photo under 100 KB for a job portal, or a signature under 20 KB? Set your limit and PNGful searches for the best quality and dimensions that fit — in your browser, with nothing uploaded.

Target size

Auto picks the most efficient format allowed. PNG is lossless, so small targets often need dimension reduction.

px
px
Strategy

Metadata is removed so every byte of the budget goes to image data.

or drag & drop an image here, or paste from your clipboard

PNG, JPG, WebP, AVIF, GIF, BMP, TIFF, HEIC, SVG

Your images are processed on your device and are not uploaded to PNGful.

Compress to 20 KBCompress to 50 KBCompress to 100 KBCompress to 200 KBCompress to 500 KBCompress to 1 MBCompress to 2 MB

How it works

  1. 1

    Set your target

    Pick a quick target like 100 KB or enter any custom limit in B, KB or MB.

  2. 2

    Choose your constraints

    Decide whether PNGful may convert the format or reduce dimensions, and set minimum dimensions if a portal requires them.

  3. 3

    Add your image

    The tool runs a quality search automatically and shows the result with its final size, quality and dimensions.

  4. 4

    Download a file that fits

    The download is at or under your target whenever it's technically possible — and tells you honestly when it isn't.

Common uses

  • Government and visa portals with strict KB limits
  • Job applications that cap photo and document sizes
  • School and university admission systems
  • Email providers with attachment limits
  • Marketplace listings with per-image size caps
  • Forum avatars and signatures with tiny limits

How the exact-size search works

The tool decodes your image once, then runs a binary search over encoder quality: encode, measure, adjust, repeat. Each attempt tells it whether to aim higher or lower, so it converges on the best quality that fits your budget in a handful of encodes.

If even the lowest acceptable quality is too big, and you've allowed it, dimensions are reduced — scaled proportionally based on how far the result is from the target — and the quality search runs again at the new size. The final download is the largest, highest-quality version found at or under your limit.

Every attempt happens locally in a background worker, so the page stays responsive and your image never leaves your device. The full algorithm is documented in our resource guide on how exact-size image compression works.

Good to know

  • Lossless PNG output can't hit arbitrary small targets for photos — allow JPG/WebP conversion or dimension reduction for small budgets.
  • Extremely small targets (a detailed photo at 10 KB) force visible quality loss or small dimensions; the tool will show you exactly what it achieved.
  • If your constraints make a target impossible (e.g. 20 KB with a 2000 px minimum width), you get the closest achievable file plus a clear notice — never a silent failure.
  • Metadata is always removed so the entire byte budget goes to image data.

Your images stay private

Your images are processed on your device and are not uploaded to PNGful.All processing happens locally using your browser's own image engine — there is no upload step, no server-side queue, and nothing to delete afterwards. Read more in our privacy policy.

Frequently asked questions

Is the downloaded file guaranteed to be under my target?

Yes, whenever it's mathematically possible within your constraints. The search only accepts results at or below the target. If your constraints make the target unreachable, PNGful clearly labels the result as the closest achievable size instead of pretending it fit.

Which format should I choose for small targets?

Leave it on Auto. For photos, JPEG or WebP reach small sizes with the least visible damage. PNG is lossless and can only shrink by reducing dimensions, so it's the wrong choice for tight budgets unless you need transparency.

Why do sites have file-size limits at all?

Upload limits keep storage predictable and pages fast, especially for systems that process thousands of applications. They're usually enforced in kilobytes, which is why PNGful uses 1024-byte KB units — the same math most validators use.

Will the image still look good under 100 KB?

Usually yes. A 1000 × 1000 px photo at JPEG quality 75 typically lands well under 100 KB. The preview shows the exact result so you can judge with your own eyes, and raising the minimum dimensions trades size headroom for sharpness.

Can I compress to a size between the presets?

Yes — enter any custom value and unit. The quick targets (20 KB through 2 MB) are just shortcuts for the most common portal limits.

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