FastTool

TARGET-SIZE IMAGE COMPRESSOR · FREE & LOCAL

Compress an image to 20 KB, 50 KB, 100 KB or a custom KB limit.

Set a maximum file size. FastTool keeps the highest tested encoder quality under your target, then reduces dimensions only when quality alone cannot make the image fit.

  • No account
  • No upload
  • JPG · PNG · WebP input
  • 25 MB max

ONE SCREEN · ONE JOB

Make this image fit.

Image pixels stay in this tab

01

Choose an image

JPG, PNG or WebP · maximum 25 MB

02 Set the maximum size1 KB = 1,024 bytes
03 Output detailsOptional controls

Checking this browser's WebP encoder. Auto will use JPEG with the selected matte if WebP export is unavailable.

REAL OUTPUT PREVIEW

Before & after

WAITING FOR IMAGE
Your image will appear here.

We will show the original and compressed file side by side—with actual bytes, dimensions and format.

Honest boundary: quality matching uses browser codecs. A smaller dimension may be required for very tight targets, and the tool will say when that happens.

MORE THAN ONE IMAGE?Compress a batch. Download one ZIP.Up to 12 images · one target per image · no uploads

Make every image fit.

Choose still JPG, PNG or WebP images and give each one the same maximum file size. We process one image at a time, reopen every output and only include verified, under-limit results in your ZIP.

Still images only. Animated PNG and WebP files are rejected individually.

Leave both dimensions blank to start at the original size. A maximum fits the whole image without cropping or upscaling. The KB limit may require a further reduction.

1 KB = 1,024 bytes. With Auto, a fitting original can stay JPG, PNG or WebP; other images are encoded as JPEG or WebP. JPEG uses a white background for transparency. Auto uses JPEG when WebP encoding is unavailable.

Choose images to get started.

    Individual downloads stay available if one image fails. Changing any output setting clears previous results; your selected files stay ready to run again.

    HOW IT WORKS

    Quality first. Pixels second.

    1. 01
      Fit your optional bounds

      Maximum width and height are applied without stretching.

    2. 02
      Search encoder quality

      A local binary search finds the highest tested quality at or below your target.

    3. 03
      Reduce dimensions only if needed

      If minimum tested quality is still too large, dimensions step down in a controlled loop.

    Safety boundary: the tool checks JPEG, PNG and WebP file signatures before decoding. Animated PNG/WebP inputs are rejected instead of being silently reduced to one frame. For re-encoded outputs, canvas re-encoding does not copy source EXIF, GPS or IPTC fields. Files labelled “Original kept” retain their exact bytes and existing metadata. Neither mode is a forensic sanitization guarantee.

    CHOOSE A REAL LIMIT

    20 KB, 50 KB, 100 KB—or the number your form requires.

    These presets are starting points, not platform rules. Always use the maximum shown by the site you are uploading to. FastTool treats 1 KB as 1,024 bytes and aims for an output at or below that ceiling.

    TargetA practical starting point forWhat to expect
    20 KBVery strict profile-image or form limitsVisible dimension reduction may be necessary.
    50 KBSmall avatars, ID-style previews and compact uploadsDetailed photos may lose fine texture.
    100 KBApplication portals, web forms and document attachmentsA useful balance for many ordinary photos.
    200 KBWeb publishing and larger on-screen imagesMore room for detail and dimensions.
    500 KBHigh-detail web images with a generous ceilingOften reachable with quality search alone.

    Important: “to 100 KB” means no larger than 100 KB. Encoders produce discrete byte sizes, so the result may be slightly below your target rather than exactly the same number of bytes.

    WHAT GETS VERIFIED

    The download is checked, not assumed.

    01

    Signature before decode

    The declared JPG, PNG or WebP type must match the file bytes. A renamed or mismatched file is rejected clearly.

    02

    Actual output bytes

    The target verdict uses the generated Blob size—not an estimate, percentage or decorative progress number.

    03

    Reopened dimensions and format

    The encoded result is decoded again so its width, height and output type are known before the download unlocks.

    04

    Fail-closed animation boundary

    Animated PNG and WebP files are rejected instead of quietly exporting only one frame. Export a still image first.

    CLEAR ANSWERS

    Before you compress.

    The tool is designed for upload ceilings, not for pretending every image can keep its original detail at any file size.

    Can I compress an image to exactly 20 KB, 50 KB or 100 KB?

    You can set any of those limits. FastTool searches for the highest tested quality at or below the target. The result can be slightly smaller because browser encoders do not produce every possible byte count.

    Does FastTool upload my image?

    No. The selected bytes, decoded pixels, compression search and output verification stay in this browser tab. Ordinary page assets and consent-controlled analytics can still make normal website requests, but your image is not part of them.

    What happens if quality changes are not enough?

    The tool steps dimensions down in a controlled loop and tells you when it had to do so. For a very tight target, a smaller image is often the honest tradeoff.

    Should I choose JPEG or WebP?

    JPEG is broadly compatible and uses your chosen matte for transparent pixels. WebP can preserve transparency when the browser encoder supports it. Auto probes the runtime first and never silently changes an explicitly selected WebP output.

    Will compression remove EXIF or GPS metadata?

    Re-encoded outputs do not copy normal EXIF, GPS or IPTC fields. When Keep original is enabled and an image already meets every limit, the original is kept byte for byte, including its existing metadata; the result labels this explicitly. Turn that option off to re-encode every file. This is not a forensic sanitization guarantee.