You dropped a PNG into a compressor, set the target to 100KB, and it came out at four times that. You lowered the quality and nothing much happened. This is not a broken tool — it is PNG behaving exactly as designed, and the fix depends on what is actually in the image.
Why PNG resists a small target
PNG is lossless. It stores every pixel exactly, and it shrinks files by finding repetition — runs of identical colour, patterns it can describe once and reuse. That makes it superb for flat graphics and terrible for photographs.
A logo with six colours and hard edges is almost all repetition, so PNG compresses it dramatically. A photograph of a street has a slightly different colour in nearly every pixel, so there is almost nothing to repeat, and PNG faithfully stores all of it.
This also explains why the quality slider disappoints you. In JPG, lowering quality throws information away and the file shrinks. In PNG there is no quality to lower — the only levers are the number of colours, the dimensions, and whether you keep transparency.
The question that decides everything
Is it a photograph, or is it a graphic?
If it is a photograph that happens to be saved as PNG — a screenshot of a photo, a picture exported from an editor, a phone image someone converted — then PNG is the wrong format and no amount of compression will fix that. Convert it to JPG or WebP with the image format converter and watch the size collapse. The full walkthrough for the JPG route is in compressing a JPEG to 100KB.
If it is a graphic — a logo, an icon, a diagram, a screenshot of an interface, anything with flat colour and sharp edges — then keep PNG. JPG would blur the edges and add halos around text, which looks worse at any file size. Read on.
If it needs transparency, PNG or WebP are your only real options. JPG has no alpha channel at all.
Getting a real PNG under 100KB
For genuine graphics, three levers work, in this order:
- Reduce the dimensions. This is the biggest and most reliable win, and it costs nothing if the image is displayed smaller than it is stored. A logo saved at several thousand pixels wide and shown at a few hundred is carrying data nobody sees. Resize it first, then compress — the reasoning is in resizing an image to 100KB.
- Cut the colour count. PNG supports a palette mode that stores a limited set of colours instead of the full range. On a flat graphic the difference is often invisible, and the file can shrink sharply. On a gradient it shows as banding, so check the result.
- Crop the empty space. Graphics frequently carry transparent margins. Trimming them removes real pixels from the file.
Then run it through the compress to 100KB tool and see where you land. If you are still well over, the image is almost certainly a photograph, and you are back to the format question.
When to switch to WebP instead
WebP is worth knowing about here because it does both jobs. It has a lossless mode that generally beats PNG on the same graphic, a lossy mode for photographs, and it supports transparency. If whatever you are uploading accepts WebP, it is frequently the shortest route to a small file with no visible compromise.
The catch is acceptance: some forms, portals and older systems only take JPG or PNG. Check before you convert. The comparison across all three is in PNG vs JPG vs WebP.
Frequently asked questions
Why is my PNG so much bigger than a JPG of the same picture? Because PNG keeps every pixel exactly and JPG discards detail your eye barely registers. On a photograph that difference is enormous. On a flat logo it reverses, and PNG wins.
Can I compress a PNG without losing quality? Yes — PNG compression is lossless, so the pixels are unchanged. The trade-off is that lossless compression can only do so much. Reducing colours or dimensions does change the image, and that is usually where the real saving comes from.
Should I convert my PNG to JPG to get under 100KB? If it is a photograph, yes, and the result will look fine. If it is a logo, screenshot or anything with text, no — JPG will blur the edges. Keep PNG and reduce the dimensions instead.
Why did compressing my PNG barely change the file size? It was probably already optimised, or it is a photograph with little repetition for PNG to exploit. Either way the lever is dimensions or format, not quality.
Does resizing a PNG lose quality? Making it smaller is generally safe and looks clean. Enlarging a small PNG does not add detail — it just makes the existing pixels bigger and softer.
The bottom line
Ask one question first: photograph or graphic. A photograph in PNG should be converted, and the format converter will drop it under 100KB in one step. A real graphic should stay PNG, and the win comes from smaller dimensions, fewer colours and cropped margins — then finish in the compress to 100KB tool. Everything runs in your browser, so nothing is uploaded either way.
