How to compress an image
- Drop your images into the box above, JPG, PNG, WebP and iPhone HEIC all work, and you can paste straight from the clipboard.
- Pick an Output format: WebP for the smallest file, or JPG when it needs to open everywhere.
- Drag the Quality slider and watch the percentage update. Every file shows its before → after size and how much you saved.
- Too big, or too soft? Nudge the slider and drop the file in again, then press Download all.
Why compress images?
Compressing re-encodes a photo at a lower quality setting, throwing away fine detail your eye barely registers, the faint noise in a blue sky, tiny colour shifts across skin tones, while keeping every pixel dimension exactly as it was. A 4 MB phone photo typically lands between 300 and 600 KB at quality 80 with no change you'd notice on a screen. That is often an 85–90% size cut for free.
The trade-off lives at the bottom of the slider. Push quality below about 50% and JPEG starts to show its seams: blocky 8×8 squares in smooth gradients, a faint halo around hard edges, and banding in flat areas like a clear sky. Photographs hide these artefacts well because they are full of texture; logos, screenshots and text-heavy graphics with crisp edges show them first, so keep those at 85%+ or leave them as PNG.
Real payoffs: pages load faster and score better on Core Web Vitals when the largest image is a few hundred KB instead of several MB; email attachments stop bouncing off size caps; and cloud storage or a portfolio folder holds far more before filling up. Because the size and percentage saved appear next to each file, you can dial in the sweet spot in seconds rather than exporting, checking and re-exporting.
Compressing vs resizing, which do you need?
They are two different levers, and knowing which to pull saves a lot of trial and error:
- Compressing (this tool) keeps the same pixel dimensions and lowers quality. Reach for it when the dimensions are already right and you just want a lighter file.
- Resizing changes the pixel dimensions themselves and usually saves far more, a 4000 px photo displayed in an 800 px slot is carrying 25× more pixels than it shows. Use Resize Image for that, then compress the result.
- Need to land under an exact byte budget? Skip the slider entirely with Compress to 200KB, 100KB, 50KB or 20KB, each finds the best quality that fits automatically.
Frequently asked questions
How does image compression work?
Lossy compression discards visual detail your eye barely notices, subtle colour variations and fine noise, then re-encodes the result. At 70–85% quality most photos look identical to the original while shrinking to a fraction of the size.
What quality level should I choose?
75% is a strong default for web use. Use 85–90% for photos you care about or images with sharp edges and text, and drop to 50–65% only when the smallest possible file matters more than fine detail.
Should I compress to WebP or JPG?
WebP produces roughly 25–35% smaller files at the same visual quality and is the better choice for websites. Pick JPG when you need maximum compatibility with older software, printers or strict upload forms.
Does compressing change my image's dimensions?
No, the width and height in pixels stay exactly the same; only the file size drops. If you want smaller dimensions too, use Resize Image and then compress.
Will compressing an already-compressed image hurt it?
A little. Each lossy save adds a small amount of generation loss, like a photocopy of a photocopy. For the best result, always start from the original file rather than re-compressing an export.
Is there a file size or batch limit?
No. Everything runs on your own device, so there are no server-imposed limits, drop as many images as you like and compress them all for free.