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Image compression guide

How to compress an image to 100 KB, 500 KB or 1 MB

Portals say "max. 100 KB", "under 500 KB" or "1 MB per image", and a quality slider does not know what that means. A target-size workflow starts with the byte limit and searches for the best result that actually stays below it, for JPG, PNG, WebP and AVIF.

From guidance to a reviewable result

Use the method when it fits. Use the tool when repetition begins.

  1. The problemA quality percentage does not prove that a file will meet a portal byte limit.
  2. Concrete exampleSearch quality first, keep dimensions when possible and resize only after explicit permission.
  3. Matching toolTarget Size Image Compressor produces compressed files in one zip.
Test a prepared byte target

Published by WoluTools · Updated 29 August 2026

Start with the real limit

Enter the maximum accepted size in KB and decide whether the original dimensions must remain unchanged. The result should count as successful only when its encoded byte size is at or below the selected limit.

Quality search comes before resizing

For JPEG, WebP and AVIF, an encoder can try a high quality, measure the output and search a bounded quality range for the highest setting that fits. The estimate must come from a real encode because image detail, noise, transparency and metadata can change the result dramatically.

Some targets cannot be reached at full dimensions

If the lowest permitted quality is still too large, the honest result is “needs adjustment.” Resizing should remain off unless the user explicitly allows it. Once allowed, reduce dimensions in controlled steps and repeat the quality search. A successful result must never exceed the target.

Choose the format deliberately

  • JPEG: broadly compatible and useful for photographs; transparency needs a confirmed background.
  • WebP: supports transparency and often provides small web files.
  • AVIF: can compress efficiently but may take longer to encode.
  • PNG: useful for lossless graphics and transparency, but a strict photographic target cannot be promised through quality search.

Check more than the percentage saved

Review the exact output bytes, dimensions, format and visible detail. A large percentage is not automatically a good result if text, product edges or colour gradients have become unusable. Metadata removal can reduce size and remove camera or location data, but colour-profile handling still needs controlled processing.

Test a real target on a prepared image

The public WoluTools demo shows measured 100 KB, 500 KB and 1 MB outcomes from the actual image worker.

Open the target-size demo