What image compression actually does
The Image Compressor re-encodes your picture to a smaller file while keeping it visually close to the original. You control the tradeoff with a quality slider from 10 to 95, and an optional toggle converts the output to WebP for further savings. After processing, the tool reports the original size and the new size side by side, so the result is measured, not guessed. The compressed file is hosted on HotIMG with the before and after byte counts shown side by side, so you can see exactly what a given quality setting cost you.
PNG input gets special handling: since PNG is a lossless format without a quality dial, the tool reduces its palette intelligently. For photographic PNGs, switching on the WebP toggle achieves far bigger reductions than PNG optimization ever could.
Picking a quality setting
| Quality | What you get | Good for |
|---|---|---|
| 85 to 95 | Visually identical, moderate savings | Portfolios, print handoffs, archiving |
| 70 to 84 | Indistinguishable at normal viewing | Websites, blogs, online stores |
| 40 to 69 | Minor artifacts up close | Thumbnails, chat images, drafts |
| 10 to 39 | Visible compression | Maximum shrinkage when looks barely matter |
When you are unsure, start at 80 and look at the result. Lossy compression works by discarding detail your eye barely registers, mostly subtle color variation in busy areas, which is why halving a file with no visible change is routine rather than lucky. The lossless-looking compression guide explains the mechanics and where the limits are.
Why bother compressing
- Page speed. Images are the heaviest part of most pages, and smaller files directly improve load time, bounce rate, and Core Web Vitals scores that search engines measure.
- Upload limits. Email attachments, forum posts, ticketing systems, and web forms all enforce caps that a compressed file slides under without drama.
- Storage. Smaller files stretch any quota, including the 25 GB that comes with a free HotIMG account, so the same space holds several times as many pictures.
- Bandwidth courtesy. Mobile visitors on slow connections feel every megabyte you did not trim, and so does anyone downloading your attachment.
Tips for compressing without artefacts
- Fix dimensions before quality. A 4000px photo shown at 800px wastes most of its weight, so run it through the resizer first, then compress.
- Compress once, from the best source you have. Repeatedly recompressing a JPG stacks artifacts.
- Use the WebP toggle for web work. It typically cuts another quarter to a third off JPG sizes, and the complete WebP guide covers browser support and when to avoid it.
- Keep the untouched original somewhere safe. Compression is one-way, and you cannot recover discarded detail later if you need a print-quality version.
- Need a different format rather than a smaller file? That is a job for the image converter.