How it works
Last updated: July 2026
ConvertCanvas converts your images inside your web browser using WebAssembly. When you add a photo, your own device decodes and re-encodes it — no file is ever uploaded to a server. That makes it both faster (no upload or queue) and completely private.
Three steps
- Drop your files. Drag images (or whole folders) into the converter, or browse from your device. Up to 100 files, 100MB each.
- Pick your output. Choose JPG, PNG or WebP. Adjust quality, resize, rotate handling and batch renaming if you need to.
- Download. Files convert in seconds. Download them individually or as one ZIP.
Why your photos never leave your device
Most online converters upload your photos to their server, convert them there, and make you download the results. That's slow — and it means your personal photos sit on someone else's computer.
ConvertCanvas works differently. We use WebAssembly (WASM) — a technology that lets your browser run the same high-performance image codecs that desktop apps use. When you drop a HEIC file, your own browser decodes and re-encodes it. The "conversion server" is your laptop or phone.
- Private: zero image bytes are transmitted, ever. Verify it yourself: open your browser's developer tools → Network tab while converting.
- Fast: no upload + no queue + no download from a server. A typical 12-megapixel photo converts in under a second.
- Clean output: conversion removes hidden metadata (including GPS location) from your photos automatically.
What we do collect
To improve the product we log anonymous conversion events: which format pair was used, how many files, and whether it succeeded. Never filenames, never image content, never location data. Details in our privacy policy.
Which image format should I convert to?
It depends on where the image is going. As a rule of thumb: use JPG for photos you'll share or upload, PNG when you need transparency or lossless editing, and WebP for the web when you want the smallest file. The table below gives the quantified trade-offs.
| Format | Compression | Typical size vs JPG | Transparency | Best for |
|---|---|---|---|---|
| HEIC/HEIF | Lossy | ~50% smaller | No | iPhone storage (limited app support) |
| JPG | Lossy | Baseline | No | Universal sharing & uploads |
| PNG | Lossless | 2–5× larger | Yes | Editing, graphics, transparency |
| WebP | Lossy or lossless | 25–35% smaller | Yes | Modern websites |
Figures are typical ranges for photographic images at equivalent visual quality; exact results vary by image content.