Image Compressor Guide: Every Setting, Explained
A complete walkthrough of ToolCraft's Image Compressor — quality, formats, output and how to read the results.
Aria Chen
Senior Tech Editor
The Image Compressor looks simple — upload, slide, download — but the settings tell a richer story. Here is what each control does and how to get the best result on the first try.
Uploading
Drag and drop, browse, or paste an image from your clipboard. JPG, PNG, WebP, GIF and BMP are accepted. Large files (20 MB+) are handled, but resizing first will make the compression faster and the result smaller.
The quality slider
Quality controls how much data the encoder keeps. It runs 1–100; the tool defaults to 80. The key fact: quality is not linear. Dropping from 100 to 80 removes a lot of redundant data with little visible change; dropping from 60 to 40 removes data you will actually see.
| Quality | Best for |
|---|---|
| 90–100 | Final deliverables where every detail matters |
| 75–85 | Web publishing — the sweet spot |
| 50–70 | Thumbnails, email attachments |
| <50 | Placeholders and previews only |
Output format
JPG, PNG and WebP output. WebP is almost always the smallest at equal quality; PNG preserves transparency; JPG is the compatibility default. For photos without transparency, WebP wins. The tool shows the output size before you commit.
Reading the results
The panel shows original size, compressed size and the reduction percentage. The side-by-side preview lets you compare at 100% zoom. If the compressed image looks identical — which it usually does at 80% — you have found your number.
Check "export WebP" when the target is a website. The same quality costs 30–50% fewer bytes than JPG.
Can I compress multiple images at once?
Not yet — the current version compresses one image at a time. Batch processing is on the roadmap.
Does compression work offline?
Yes. The entire tool runs in your browser; once loaded it works without a connection.
Written by Aria Chen
Aria writes about web technology, image formats and developer workflows. She has spent 10+ years building and documenting web products.
Tools used in this article
Image Compressor
PopularShrink JPG, PNG and WebP files without losing visible quality.
Resize images to exact dimensions, scales or target sizes.
Crop images to any rectangle or preset aspect ratio.
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