Image compressor to 50KB

How this works

The compressor keeps the decoded original in memory alongside the result, so the comparison slider is showing you two real images rather than a simulation. Quality is found by bisecting the JPEG quality range against your 50KB target, and the panel prints the quality it settled on alongside the final pixel dimensions. Those two numbers tell you whether the target was reached cheaply or expensively.

What it cannot do

• Both images live in memory while you compare them, so a very large original will use noticeably more of it than compression alone would.
• The comparison shows you the file as your browser decodes it. A print job or a different colour profile can look different again.

Questions people actually ask

What am I actually looking at in the comparison?

The original decoded bitmap on one side and the compressed result on the other, at the same display size. If the compressed side was downscaled, your browser is scaling it back up to match, which is itself part of what the loss looks like in practice.

What quality number should I expect?

It depends entirely on the photograph. A flat graphic or a screenshot often reaches 50KB at quality 0.8 or higher. A detailed outdoor photo at full resolution can land near 0.2 before it fits, and that is where artefacts become obvious.

Can I stop it reducing the resolution?

The tool prefers keeping the resolution and only steps down once quality has bottomed out, so if you see a smaller output it means the full-size version could not fit at any quality worth having. Raising your target is the way to keep the pixels.

Does the before-and-after comparison send anything anywhere?

No. Both images are held in your browser’s memory and drawn to the screen from there. Closing the tab discards both, which is also why there is no link you can send someone to show them the comparison.