Bulk WebP Converter — 1000+ Images at Once
Drop a folder. Get a ZIP. No upload, no cap, no queue. The worker pool scales to every CPU core you have, so throughput grows with your machine — not with a server quota.
In-browser bulk WebP conversion
Drop a folder of mixed JPG, PNG, HEIC, TIFF and GIF files below. The engine auto-detects each format, spawns one worker per CPU core, and packs the results into a single ZIP with the original folder structure preserved.
Supported input formats
- ✓ JPG / JPEG — Photos, portraits, web content
- ✓ PNG — Screenshots, icons, transparent images
- ✓ HEIC / HEIF — iPhone photos, Apple formats
- ✓ TIFF — Scans, prints, high-resolution archives
- ✓ GIF — Animations and static GIFs
- ✓ BMP, PSD & more — Anything ImageMagick can decode
How the conversion works
- 1. DropDrag files or a whole folder into the box below. Folder structure is preserved in the output ZIP.
- 2. AnalyzeEach image is analyzed for entropy and content type. The engine picks per-image quality settings targeting PSNR ≥ 44.5 and SSIM ≥ 0.95.
- 3. EncodeConversion runs on all of your CPU cores in parallel via Web Workers. EXIF, ICC color profiles and geolocation are copied onto the WebP output.
- 4. DownloadWhen the batch is done, a ZIP containing every converted WebP downloads automatically. No re-upload, no waiting on a server.
Throughput that scales with your machine
Most batch converters cap you because their servers cost money per image. SciZone runs on your CPU, so the only limit is how much silicon you brought.
Why most bulk converters quietly cap you
Free online converters usually have a hidden cap: 20 files per batch, 10 MB per file, queues that reset, watermarks on the free tier. The reason is simple — they run on someone else's server, which costs money per conversion. SciZone runs on your machine, so the economics flip: more files cost the server nothing, only your CPU time.
True multi-core parallelism
When you drop a batch, SciZone spawns one Web Worker per logical CPU core (detected via navigator.hardwareConcurrency). On an M2 MacBook that means 8–12 parallel encoders; on a desktop workstation it can be 16 or 24. Each worker runs the full 13 MB WebAssembly converter independently, so throughput scales close to linearly with core count.
Mixed formats in one drop
You do not need to pre-sort your files. Drop a folder containing JPG photos, PNG screenshots, HEIC iPhone exports and TIFF scans all mixed together — the engine auto-detects each file and picks the right decoder. The output ZIP keeps your folder structure, so you can drop it back in place.
What 'no upload' actually means at scale
When you convert 2000 photos through an online tool, you upload 2000 files (easily 10–20 GB), wait for a server to process them, then download 2000 more. SciZone transfers zero bytes to anyone during a batch run — verify it in DevTools → Network. The only server traffic is the initial page load, and even that is cached by the service worker for offline use.
How the bulk converter works
Four steps. Drop 10 files or 10,000 — the pipeline is the same.
- 1
Drop an entire folder
Drag a folder (or several folders) onto the drop zone below. Nested subfolders are supported. Any non-image files in the folder are passed through unmodified in the output ZIP.
- 2
Parallel processing starts immediately
Worker threads fire up the moment files land — no upload step to wait for. A live progress counter (X of Y) shows the batch status. Workers recycle every 32 jobs to keep memory stable on huge runs.
- 3
Per-image quality tuning
Every photo gets its own PSNR/SSIM-targeted encoder. A noisy portrait is compressed differently from a flat icon or a text-heavy screenshot. You do not pick a quality — the engine does, per file.
- 4
One ZIP for everything
When the last file finishes, the browser saves a single ZIP containing every converted WebP with the original folder structure. Drop 1000 images, get one ZIP of 1000 WebP files, ready to ship.
Typical Results
See how much space you can save. Quality stays the same, file sizes shrink dramatically. Click images to view full size.
Average Results
Based on thousands of optimized images
Bulk WebP Converter — Frequently Asked Questions
How many images can I convert in one batch?
There is no hard cap. Users routinely run 1000–2000 images per batch. The practical ceiling is your device's RAM; workers recycle every 32 jobs to keep memory from growing unbounded. For 5000+ image runs we recommend processing in chunks of ~1500 with the browser tab as the only heavy workload.
What is the largest file size supported?
There is no enforced file size limit. The real limit is WebAssembly's 4 GB per-instance memory ceiling, so a single image bigger than ~2 GB uncompressed (for example, an 800-megapixel TIFF) may fail. For normal photography — even multi-hundred-megabyte TIFF scans — there is plenty of headroom.
Does the batch size slow the browser down?
The converter is CPU-heavy by design, so your fan will probably spin up on a 1000-image batch. The UI itself stays responsive because all encoding runs inside Web Workers, not on the main thread. You can keep scrolling, reading FAQ, even starting a second batch.
Can I mix JPG, PNG, HEIC and TIFF in one drop?
Yes. The engine auto-detects each file's format and routes it through the right decoder. A folder with mixed iPhone HEIC photos and DSLR JPGs and Photoshop PNGs all converts in a single run.
Does folder structure get preserved?
Yes. If you drop a folder like `vacation/day1/beach.jpg`, the output ZIP contains `vacation/day1/beach.webp`. Non-image files (like PDFs or text notes) are passed through unchanged, so you can extract the ZIP on top of the original folder and have a clean WebP-ified copy.
Will my batch run if I close the tab mid-conversion?
No — the conversion is tied to the tab. Closing the tab stops the workers. For very large runs, keep the tab open until the ZIP download starts. Successful conversions are cached in IndexedDB, so if you refresh accidentally you can resume most of the batch.
Is there a command-line version for automated pipelines?
A native CLI and npm package are on the roadmap — they will expose the same WebAssembly engine through a shell command and a Node.js import. For current automation, you can run the in-browser version through Playwright or Puppeteer.
How does SciZone compare to TinyPNG or ImageOptim for batch work?
TinyPNG has per-file limits and a server-side queue. ImageOptim is macOS-only and not WebP-native. SciZone is cross-platform, WebP-first, has no queue, no file cap and no upload. For pure throughput on a single machine, SciZone's multi-worker pool is faster on most modern CPUs.
Why Choose SciZone?
We're not just another optimizer. We engineered a fundamentally better solution.
| Feature | SciZone (You're here) | Other Optimizers |
|---|---|---|
| CPU Utilization
How processing power is used
| True Multi-Threading Intelligently uses all CPU cores without overloading your system | Single-Threaded Uses only one CPU core, wastes available power |
| Quality Settings
How compression is optimized
| Unique Per Image Algorithm analyzes each photo and picks optimal settings | One-Size-Fits-All Same settings for every photo, inconsistent quality |
|
Metadata & Color Profiles
Preservation of image data
| Fully Preserved EXIF, color profiles, geolocation. Everything stays intact | Often Stripped Color profiles lost, metadata incomplete |
|
Quality-Size Balance
Optimization results | Perfect Balance Maximum compression with imperceptible quality loss | Inconsistent Either too large or noticeable quality loss |
The Bottom Line
Every photo is unique. Our intelligent algorithm understands this and analyzes each image individually to find the perfect balance between file size and quality. We utilize your computer's full power without overloading it, preserving every detail of your metadata and color profiles. Your files are smaller, faster, and absolutely perfect. 🎯