画像コンバーター

PNG・WebP・JPEG 間で画像を変換し、必要ならサイズも変更。すべてブラウザ内で完結し、アップロード一切なし。

Image Converter is a tiny, focused tool for moving images between the three formats you actually need on the web — PNG, WebP, and JPEG — and resizing them at the same time. Everything happens inside the popup using the browser's built-in `<canvas>` element. **No images ever leave your machine. No uploads, no servers, no network requests.** Key features: - Drag-and-drop a PNG, JPEG, or WebP into the popup (or click to choose a file). - Pick the target format: PNG, WebP, or JPEG. - For lossy formats (WebP, JPEG), a quality slider from 0.60 to 1.00. - Optional resize: enter a new width or height; "Lock aspect ratio" recomputes the other dimension automatically. - See the original size and the converted size side by side, with the % change. - Download the result with a sensible filename (`original-name.webp`, etc.). - Your last format, last quality, and aspect-lock preference are remembered locally. This extension has exactly one permission — `storage` — used only to remember your conversion preferences. It cannot read web pages, cannot read your tabs, and never makes network requests.