ToolGPT

Compress an image to under 20 KB

20 KB is one of the tightest limits an upload form can set, usually for a signature or a small photo. Attach the image, say 20 KB, and ToolGPT makes a JPEG that fits, or tells you how close it got.

  • Runs in your browser
  • No sign-in needed
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Things you can type
signature-scan.jpg
Open ToolGPTAttach a file and describe what you need.

More about the Image Compressor →

How it works

  1. 1

    Attach one image

    Add the photo or the scanned signature with the + button. A size limit works on one image at a time.

  2. 2

    Say the limit

    Type “under 20 KB”. For a large photo, add a smaller pixel size too, such as 400 px on the long side, because 20 KB only holds a small picture.

  3. 3

    Download the JPEG

    The new file keeps your file's name with “-compressed” added. Check its size on the card before you upload it.

Why 20 KB usually means fewer pixels

A JPEG's size depends on how many pixels it has and how much detail they hold. A phone photo has around 12 million pixels, and even at the lowest quality ToolGPT uses it weighs many times more than 20 KB. To fit, the picture itself has to be small: a few hundred pixels across is typical for a 20 KB photo.

ToolGPT tries quality settings from 92 down to 30, keeping the pixel size you chose, and stops at the first one that fits. You get the best quality that is still under the limit. If even quality 30 is too big, you don't get a file that breaks the limit: ToolGPT tells you the smallest size it reached, and you can ask again with a smaller long edge.

Signatures and scanned documents

A signature on white paper is mostly empty space, which compresses well, so it often fits easily once it is cropped close to the ink. Ask ToolGPT to crop first: the crop shapes are drawn on your own image, and a custom crop box lets you drag to the exact area.

Grey shadows and paper texture cost bytes. A flat scan in good light comes out smaller than a phone photo taken at an angle. Everything runs in your browser, so the scan never leaves your device.

Frequently asked questions

Is 20 KB 20,000 or 20,480 bytes?

ToolGPT's file cards count 1 KB as 1,024 bytes. Some forms count 1,000 bytes instead, so for a strict limit ask for a little less, such as 19 KB.

Can I compress several images to 20 KB each?

Not in one go. A size limit applies to one image, so compress them one at a time.

Will the image look worse?

At 20 KB some loss is unavoidable. A picture made smaller in pixels usually looks better than a large one squeezed to the lowest quality.

Try it with your own file

Open ToolGPT, attach a file, and type what you want done.

Open ToolGPT

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