Image Compressor
Reduce image size in your browser — JPEG/WebP/PNG quality compression and resizing, processed locally. Free, unlimited.
画像をここにドラッグ＆ドロップするか、クリックして選択
Supports JPG / JPEG / PNG / WEBP, up to 40MB
- 圧縮はブラウザ内で即座に完了します（大きな画像：約1〜5秒）
- 結果は24時間保持され、その後自動削除されます
- タスクは自動保存されます：ページを閉じても24時間以内に戻って確認できます（最後のタスクのみ保持。シークレットモードやブラウザキャッシュ削除は避けてください）
処理完了後、結果がこのアドレスに送信されます（1回のみ）
Paint over areas to remove
Paint over the people, objects, watermarks or blemishes to remove — AI will fill the background. Cover the area fully for best results.
アップロード後、圧縮結果がここに表示されます
How Image Compression Works
Image compression balances visual quality against file size. JPEG is lossy: a discrete cosine transform (DCT) converts the image from the pixel domain to the frequency domain, discarding high-frequency details the human eye barely notices, then quantizes and entropy-codes the coefficients — stronger quantization means smaller files and more visible artifacts. PNG is lossless: it uses the DEFLATE algorithm to compress without losing a single pixel, ideal for lossless needs and transparency, though usually larger. WebP supports both modes and is typically 25%+ smaller than JPEG at comparable quality. This tool runs all encoding in your browser, so no compression data is sent for processing — faster and more private.
Who It's For
Image compression helps whenever pictures need to travel: websites and newsletters load faster with smaller images; email and messaging apps have attachment limits; e-commerce product shots and ID photos need the right balance of clarity and size; photo archives and asset libraries free up storage. No sign-up needed — just open the page and compress for free.
FAQ
Is this tool free?
Yes, completely free with no sign-up and no usage limits.
Which image formats are supported?
JPG, JPEG, PNG and WEBP, up to 40MB per file.
Where does the compression happen?
Compression runs entirely in your browser (no server queue — faster). To support history and sharing, the source and result are still uploaded and kept for 24 hours, then deleted automatically.
How do I get the best result?
For photos, use JPEG at quality 70-80 (visually identical). Use PNG for transparency or fine linework (lossless). Choose WebP for the smallest size. If the image is very large, resizing it first can cut the size by 90% or more.
Can PNG be compressed?
Yes. PNG is lossless, so every detail and the alpha channel are kept. If you need a smaller file, convert to WebP (supports transparency, smaller) or JPEG (no transparency).
What is the output format?
The format you choose (same as the original by default). The download is named "name-compressed.extension".
Is my file stored?
No. Images are automatically deleted within 24 hours after processing (same as our other tools).
Can I close the page after uploading?
Yes. Your task is saved in this browser automatically — come back within 24 hours to see the results (only the latest task is kept; do not use private browsing or clear your browser cache).