Why PNGs are so hard to shrink
PNG is a lossless format: it reproduces every pixel exactly, with no quality dial to turn. That is perfect for logos, screenshots and graphics — and it is why a PNG photo can be ten times larger than the same image as a JPG, and why most “compress PNG” tools quietly disappoint. To get a PNG under 100 KB you have exactly two levers: convert it to a lossy format, or reduce its pixel dimensions. This tool offers both, and is upfront about which one it is using.
Option 1: convert to JPG or WebP (default)
If your PNG is a photo or any image with continuous tones, conversion is the right answer. The tool converts to JPG by default — telling you it did — and then runs its quality search to land just under 100 KB at the largest possible dimensions. One caveat handled for you: JPG has no transparency, so transparent regions are flattened onto a white background. If you need transparency to survive, choose WebP output, which supports it and compresses even better.
Option 2: keep it PNG
For screenshots with text, UI mockups, pixel art or logos where crisp edges matter, select “Keep original format.” Since PNG has no quality setting, the tool instead binary-searches the image's dimensions, finding the largest scale that fits 100 KB losslessly. Expect a real size reduction — a full-HD screenshot may come back around half its original width — but with edges that stay perfectly sharp, which is the point of PNG.
Which should you pick?
- Photo saved as PNG (often from a scanner or an export gone wrong): convert to JPG. No visible downside, massive size win.
- Screenshot with text you must read: keep PNG if the downscaled size is still legible; otherwise WebP at high quality is a strong middle ground.
- Logo or graphic with transparency: WebP output keeps the transparency and hits the target easily.
As with every page here, the work happens in your browser — the file is never uploaded — and the result is guaranteed at or under 100 KB. For JPG sources, the JPG-to-100KB page covers the lossy-format details.