画像 ツール
Compress, convert, resize, view EXIF — image utilities that never upload your files.
カテゴリー紹介
Image tools online almost always upload your files. For private photos, scanned documents, or anything you'd rather not send to a third party, that's a problem. This category's image utilities run in your browser using Canvas API and WebAssembly — files never leave your device. Compress for the web, convert formats, view EXIF data, generate favicons, all locally.
活用例
- →Compress photos before email or website upload.
- →Convert iPhone HEIC photos to JPEG for cross-platform sharing.
- →Bundle multiple images into a single PDF (scans, receipts).
- →Inspect EXIF data (camera, GPS, timestamp) before sharing.
よくある質問
How can it not upload? Aren't images server-side work?
Modern browsers expose Canvas, WebCodecs, and WASM-compiled image libraries — all the same operations a server would do, running locally. Open dev tools' Network panel and confirm: no upload requests during processing.
What about file size limits?
Browser memory is the limit — typically up to 50-100 MB per image. For 4K video or RAW photo batches, desktop tools (Adobe, ImageMagick) handle larger files better.
Why is HEIC slow?
HEIC requires a WASM polyfill (heic2any) since browsers don't natively decode it. First conversion downloads the library; subsequent conversions are fast.