ロスレス圧縮
画質を落とさず画像圧縮 — 無料オンライン
より小さいファイルが欲しいけど品質が心配？高品質設定とWebPなどのモダンフォーマットで、見た目の品質を落とさずに圧縮 — すべてブラウザ内、アップロード・登録不要。比較スライダーで結果を保証。
Why use this compress lossless tool?
Compress JPEG, PNG and WebP with no visible quality loss
High-quality preset keeps images crisp
Before/after comparison slider to verify results
Batch compress multiple images at once
100% local, private, free, no signup
Frequently Asked Questions
Can I compress an image without losing quality?
Yes. At quality 80 or higher, or by converting to WebP, the visible quality is virtually identical to the original while the file size drops significantly. Use the comparison slider to confirm.
What is the best format for lossless compression?
PNG is lossless but large. For the web, WebP at high quality gives near-lossless results at a fraction of the size. Choose the format that fits your use case.
How do I check quality after compression?
Use the built-in before/after comparison slider to compare the original and compressed image side by side before downloading.
Is lossless image compression free?
Yes, completely free with no watermark, signup, or file limits. All processing happens locally in your browser.