01LOCAL ONLY
Private by design
All processing runs in your browser via WebAssembly. No file is transmitted, stored, or seen by a server. Disconnect from the internet after loading — Capcompress still works.
Open DevTools: zero network requests.
Convert PNG to WebP Online
Turn heavy PNG files into lightweight WebP images in a few clicks. Great for landing pages, e-commerce, and any project that needs faster load times.
Why Capcompress
COMPRESS WITHOUT UPLOADING.
BY DESIGN.
02MULTI-FILE
Batch & folders
Drop an entire folder. Capcompress reads it recursively, compresses every image in parallel across all your CPU cores, and exports a ZIP that mirrors your original folder structure.
Tested with 500+ images per session.
03HEIC READY
Convert between formats
Input HEIC, JPEG, PNG, WebP or AVIF. Export JPEG, PNG, WebP or AVIF with full control over quality, dimensions, and encoding effort per image or globally.
Lossless and lossy modes for PNG & WebP.
04ZERO FRICTION
No account. No limit.
No login, no install, no watermark, no file size cap, no daily quota. Open the page and start compressing — in Chrome, Firefox, Safari, and Edge.
No credit card. No catch. Ever.
How it works
COMPRESS IMAGES ONLINE.
THREE STEPS.
- Step 01
DROP
Drag & drop individual files or an entire folder. Capcompress scans it recursively — any depth, any structure. Accepted input: HEIC, JPEG, PNG, WebP, AVIF.
- Step 02
TUNE
Pick output format, quality, and target dimensions. Apply settings globally to the whole batch, or override specific images individually.
- Step 03
DOWNLOAD
Download each image individually, or export the full batch as a ZIP. The archive mirrors your original folder tree — no manual renaming needed.
Supported formats
WEBP · AVIF · JPEG · PNG.
COMPRESS OR CONVERT.
WebPRECOMMENDED
Best balance
30–80% smaller than JPEG. Transparency support. Works in all modern browsers. Lossy & lossless modes.
AVIFMAX COMPRESSION
Next-gen quality
Up to 90% smaller than JPEG. HDR & wide color gamut support. Modern browsers only. Slower to encode.
JPEGUNIVERSAL
Broadest compat
Supported on every device and platform. Great for photos. No transparency. Fastest encode speed.
PNGLOSSLESS
Pixel-perfect
No quality loss, ever. Full alpha channel. Larger files than lossy formats. Best for UI assets and graphics.
FAQ
IMAGE COMPRESSION.
YOUR QUESTIONS.
- Does Capcompress upload my images to a server?
- No. All processing runs locally in your browser via WebAssembly. No file is transmitted — not even a thumbnail. You can disconnect from the internet after loading the page and compression will still work.
- Is there a maximum file size?
- There is no hard limit. The practical ceiling depends on your device's available RAM. Most modern computers handle images up to 50–100 MB per file without issues. For large batches, Capcompress processes images in parallel to keep memory usage manageable.
- Does converting PNG to WebP lose quality?
- Only if you choose lossy compression. Capcompress lets you pick a quality level from 1 to 100. At quality 90+ the visual difference from the original PNG is imperceptible. You can also use lossless WebP to get a smaller file with zero quality loss.
- Is WebP supported in all browsers?
- Yes. Chrome, Firefox, Safari (since 14), Edge, and Opera all support WebP. WebP is safe to use for any modern website. For legacy support you can use the HTML <picture> element with a PNG fallback.
- Are my PNG files uploaded to a server?
- No. Capcompress processes everything 100% locally in your browser using WebAssembly. Your images never leave your device, which means no upload time, no privacy risk, and no file size limit imposed by a server.
- Can I convert multiple PNG files at once?
- Yes. Drop an entire folder into Capcompress and every PNG inside will be converted to WebP automatically. The result is downloadable as a ZIP that mirrors your original folder structure.
Ready?
START COMPRESSING.
Drop your images at the top of the page — or click below.
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