Why does my PNG upload get converted to JPEG?

JPEG's adjustable compression is what enables the quality/size tradeoff this tool offers — PNG uses lossless compression without that same dial.

Is there a setting that guarantees no visible difference?

It depends on the image — 90%+ is visually lossless for most photos, but the exact threshold varies by content and viewing conditions.

Why does the output always become a JPEG?

JPEG's lossy compression is what enables an adjustable quality-vs-size tradeoff — formats like PNG use lossless compression without a comparable dial.

Is my image uploaded anywhere?

No — compression runs entirely in your browser using the canvas API; the image data never leaves your device.

What's the lowest quality setting I can pick?

10% — the slider runs from 10% to 100%, so you can't push it all the way down to 0% quality.

Can I compress a GIF or WebP image?

You can upload one, but the output is always a static JPEG — the canvas only captures a single rendered frame, so an animated GIF's motion won't survive the process.

Does compressing at 100% quality leave my file identical to the original?

Not necessarily — the image is always re-encoded as JPEG, even at 100% quality, so a PNG (or already-JPEG) original can still change size in either direction due to how JPEG encodes pixel data.

Why did my file get bigger instead of smaller?

That can happen with an already heavily-compressed JPEG at a high quality setting, or a very small, simple image — JPEG's own file-header overhead can outweigh any savings from re-encoding in those cases.

Image Compressor

About the Image Compressor

Reduces an image's file size by adjusting JPEG compression quality, letting you trade off visual quality against smaller file size directly in your browser.

100% Free Runs in Your Browser No Sign-Up Required

How to use it

Upload an image.
Adjust the Quality slider.
Click Compress, then download the result.

Formula

Re-encodes the image as JPEG at an adjustable quality setting (0-100%), controlling how aggressively compression discards visual detail to reduce file size.

Worked example

A 5MB photo compressed at 70% quality might shrink to under 1MB with only subtle, often unnoticeable, quality loss.

Recommendations

• Start around 70-80% quality — usually the sweet spot for a large size drop with minimal visible quality loss.
• Photos with fine detail, like foliage or text, show compression artifacts more readily than smooth images at the same setting.
• Compress from the original whenever possible — compressing an already-compressed image compounds quality loss.

Frequently asked questions

No — this only adjusts compression quality, keeping the original pixel dimensions. Use the Image Resizer to also change width and height.

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