Drop your PNGs
Screenshots, graphics, logos — all fine. Mixed folders work too.
Compress PNG files without uploading them
PNG is lossless, which is why it is huge. Either re-encode at a lower bit depth or convert to WebP — both run locally in your browser.
Drop images here
or · JPG, PNG, WebP, GIF
How it works
Pick WebP or keep PNG
WebP typically saves 70–90% on PNG sources and keeps transparency. Keeping PNG re-encodes at full quality with no gain in most browsers.
Download the ZIP
You get a per-file before/after report so you can see exactly what each conversion saved.
Questions
Why are PNG files so large?
PNG is a lossless format — it stores exact pixel data with no quality loss, which costs bytes. Photographic content inside a PNG is especially wasteful.
Does converting to WebP lose transparency?
No. WebP supports a full alpha channel, so transparent logos and screenshots keep their transparency, unlike a JPEG conversion.
Will the image look different?
At quality 80–90 the difference is usually imperceptible on screenshots and UI graphics. Photos stored as PNG will look slightly softer than the original — that is the trade for the size reduction.
Is my file uploaded to a server?
No. The browser reads the file from your disk and processes it in memory. Zero network requests after page load.
PNG output options, honestly compared
PNG is lossless by design, which means you cannot meaningfully "compress" a photograph as PNG. The real choice is what to convert it to.
| Case | Value | Why it matters |
|---|---|---|
| PNG, lossless | Baseline | No quality loss. Large for photographs. Correct for logos, icons, screenshots and anything with hard edges. |
| WebP, lossless | 10–30% smaller than PNG | Identical pixels, alpha preserved. The right answer for UI graphics. |
| WebP, lossy quality 82 | 60–80% smaller | Best for photo-realistic PNGs. Alpha still preserved. |
| JPEG quality 85 | 80–90% smaller | Smallest, but flattens transparency to white and adds ringing around sharp edges. |
| PNG-8 (256 colours) | Up to 70% smaller | Not available here — only safe for flat graphics with few colours. |
| AVIF | Smallest of all | Better numbers, but slow to encode and not exposed by the canvas API. |
Five mistakes that waste the most time
Trying to compress a photograph as PNG
PNG has no quality slider. The only levers are dimensions and colour depth. Converting to WebP or JPEG is the actual solution.
Screenshotting to PNG then mailing it
A 4K screenshot PNG can hit 8 MB. WebP lossless cuts it by a third with zero pixel change.
Converting a transparent logo to JPEG
The transparent area turns white, which is obvious on any non-white page. Use WebP or keep PNG.
Repeatedly re-saving PNG
Harmless for quality — PNG is lossless — but pointless. Nothing shrinks after the first pass.
Assuming smaller files mean worse quality in PNG
Genuinely optimised PNGs use better filters and smaller palettes with zero pixel change. That is not what this tool does; this tool converts format.
Free web version vs the $19 desktop app
| Free, this page | Bulk Image Kit $19 | |
|---|---|---|
| PNG output at all | Only via "keep original" | Yes, explicit PNG option |
| Alpha preserved | Yes in PNG and WebP | Yes in PNG and WebP |
| Batch limit | 20 images | Unlimited |
| Per-image format | No | Yes |
| Offline | After first load | Always |
More questions
Can PNG be compressed without losing quality?
Yes — tools like pngquant, oxipng and zopflipng re-encode with better filters. This browser tool does not; it converts format instead, which usually shrinks files more.
Why is my PNG still huge after processing?
Because PNG is lossless and the source was photographic. Convert to WebP lossy at quality 82 for a 60–80% reduction.
Does converting PNG to WebP keep transparency?
Yes. The alpha channel survives the conversion. That is the main reason to prefer WebP over JPEG here.
What is the smallest format for screenshots?
Lossless WebP in most cases. For screenshots with lots of flat colour, PNG with a reduced palette can beat it, but that needs a dedicated optimiser.
Need more than 20 at a time?
Bulk Image Kit is the same engine as a single offline file — unlimited images, resize + compress + watermark + rename, one-time $19, no subscription.
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