Compress HEIC to 100KB PNG — lossless.

Some forms and systems accept PNG but not JPEG — and cap uploads at 100KB. That combination is awkward, because PNG is lossless and 100KB does not hold many pixels when every one must be preserved exactly. This tool solves it: you type 100, and it produces a lossless PNG at or under 100KB, with no upload and no guesswork.

The honest reality is that a 100KB PNG is necessarily small in resolution — typically around 250–300 pixels on the long edge for a photograph. That is the cost of lossless at a tight size. If your form accepts JPEG and the content is a photo, you will keep dramatically more resolution with a 100KB JPEG. Reach for the PNG path when PNG is required, or when you specifically need lossless output.

Who needs a 100KB PNG

• PNG-only forms. Some government, medical, and enterprise portals accept PNG uploads and reject JPEG and HEIC outright, while still enforcing a 100KB ceiling.
• Lossless previews and thumbnails. A small, pixel-perfect image — a contact sheet entry, a preview tile, an evidence thumbnail — that must stay under 100KB without encoding artifacts.
• Graphics and screenshots. Diagrams, charts, UI screenshots, and line art where JPEG would blur sharp edges; PNG keeps them crisp even at a small size, and often compresses graphics far more efficiently than photos.
• Systems built around scanned documents. Document workflows frequently standardize on PNG and impose a per-file size cap.

In every case the requirement is the same: a PNG, at or under 100KB, ideally without looking degraded. That is exactly what this tool produces.

How to compress HEIC to 100KB PNG, step by step

1. Open the compressor on this page. The engine loads once, in your browser, the first time you visit.
2. Drop your HEIC photo into the box, or click to select it. The moment you choose a file, the tool decodes it and shows a preview so you can confirm you picked the right one.
3. Set the target to 100KB. It is preset, but you can type any number.
4. Click Compress. The tool reduces dimensions until the lossless PNG fits under 100KB, usually within a second or two.
5. Compare the before and after. The original is shown next to the result so you can see exactly what changed.
6. Download the result. You get a .png file named with the target size, ready to upload.

If the form rounds up at the boundary, type a slightly lower number (say 95KB) and compress again.

How PNG compression to a target size works

PNG has no quality setting — it is lossless by design. So unlike JPEG, you cannot dial quality down to hit a size target. Instead, the tool reduces the dimensions of the image until the lossless PNG fits. It runs in three stages, all inside your browser.

1. Decode the HEIC

HEIC stores image data compressed with HEVC. Browsers other than Safari cannot render HEIC directly, which is why an <img> pointed at a raw HEIC shows nothing. The tool uses a WebAssembly module to decode the HEIC into raw pixels, entirely on your device. No pixel data is ever sent anywhere.

2. Reduce dimensions with a Lanczos filter

To fit 100KB losslessly, the tool resizes the image down using a Lanczos resampling filter — the gold standard for downscaling, which preserves edges and detail far better than the bilinear filters many tools default to. For large source photos it estimates the target dimensions from the file size first, so it does not waste time encoding the full image repeatedly; then it refines with real encodes.

3. Encode losslessly and verify

The resized pixels are encoded as PNG, and the tool checks the resulting byte size. If it is still over 100KB, it shrinks a little more and re-encodes, looping until it lands at or under the target. The final PNG is lossless — every pixel of the (resized) image is preserved exactly.

What to expect from a 100KB PNG

• Low resolution is normal. A photograph at 100KB PNG typically lands around 250–300px on the long edge. There is no way around this: lossless fidelity at a small byte budget means few pixels.
• Graphics compress better. If your image is a screenshot, diagram, or logo with flat areas and sharp edges, PNG reaches useful dimensions at 100KB where a photograph cannot — PNG handles synthetic content far more efficiently than photos.
• No quality loss. Whatever resolution you end up with, the encode is lossless — no blockiness, no ringing, no artifacts. The pixels are exact.

If your image is a photograph and resolution matters, the single most effective change is switching to JPEG: a 100KB JPEG keeps roughly 800–1200px on the long edge, several times what PNG can manage at the same size.

PNG vs JPEG at 100KB

The rule: PNG when the format or losslessness is required; JPEG for photos where resolution matters. Both hit 100KB exactly; they just spend the byte budget differently.

Privacy: nothing leaves your device

The images people compress to 100KB — ID photos, document scans, certificate images — are often sensitive, so this deserves to be said plainly.

Your image never leaves your device. There is no upload, no cloud processing, no server that sees your photo. Decoding and compression happen locally, inside your browser, using a WebAssembly module. When you close the tab, the data is gone. There is no account, no storage, and no analytics applied to your image.

This is a meaningful difference from most “online compressor” websites, which upload your photo to a server, process it there, and send it back. For sensitive images, running everything locally is both a privacy guarantee and a speed advantage.

Related target sizes

Not every PNG form wants exactly 100KB. The same tool hits any target:

• 50KB PNG — tighter caps that require PNG.
• 200KB PNG — a more generous PNG allowance, keeping more resolution.
• 100KB JPEG — the right choice if the form accepts JPEG and the image is a photo.

Whatever number your form states, type it and the tool lands at or under it — privately, in your browser, with no upload.