Image Compressor は何をしますか？
Image Compressor はブラウザ上でデータやファイルを変換するツールで、結果と制限を明確に示します。 検証済みの機能： JPEG, PNG, and WebP input, Quality control, Maximum width 12,000 pixels, Metadata removal.
Choose format by image content
Use JPEG for opaque photographs, PNG for lossless graphics or transparency, and WebP for modern web delivery after checking target-browser support.
使い方
- Choose one JPEG, PNG, or WebP file smaller than 30 MB.
- Select output format, quality, and a maximum width up to 12,000 pixels.
- Compress the image, compare exact file sizes, and download the result.
実際の入出力例
Re-encode a photograph as WebP
入力
photo.jpg, quality 80%, maximum width 1600 px出力
photo-output.webp with measured byte sizeThe browser scales the pixels when necessary and encodes a new WebP file without the source EXIF metadata.
一般的なエラーと対処
| 症状 | 原因 | 対処 |
|---|---|---|
| The file cannot be decoded. | It is damaged, mislabeled, or unsupported by the browser. | Open and export a valid JPEG, PNG, or WebP copy first. |
| The output is larger. | The selected format or quality is less efficient for this image. | Compare WebP or JPEG and reduce quality or dimensions when transparency is not required. |
File size depends on pixels and format
このツール固有の制限： A smaller dimension or lossy format can reduce size, but PNG or a high quality setting can create a larger file. Very large pixel dimensions can exceed device memory.
標準と実装の参考資料
- MDN — Web image formats (opens in a new tab)Compares compression and transparency support.
- MDN — HTMLCanvasElement.toBlob() (opens in a new tab)Documents the browser export API.
Image Compressor — FAQ
Are images uploaded?
No. Decoding, canvas rendering, and file creation happen in the current browser tab.
Does compression remove EXIF?
Yes. Canvas re-encoding removes source EXIF and most other metadata.
Why can output be larger?
PNG or a high quality setting can exceed an already optimized source.
更新内容
実質的な更新： Image Compressor: Added local JPEG, PNG, and WebP re-encoding, quality and width controls, metadata removal, exact size comparison, and download.