Change 画像 Opacity
「Change 画像 Opacity」は画像とデザインに使えるブラウザツールです。入力内容と結果は通常この端末内で処理され、登録は必要ありません。
JPEG, PNG, or WebP only; up to 20 MB and 40 megapixels. Processing stays in your browser.
0% makes every pixel fully transparent; 100% keeps the decoded source opacity.
LIVE PREVIEW
Choose an image to begin
Select a supported local image to preview its opacity.
Output is limited to 10,000 pixels per side and 40 megapixels.
PNG preserves the adjusted transparency. JPEG input is decoded and exported as PNG because JPEG cannot store transparency; the new PNG has no source metadata.
使い方
使い方
- Choose a JPEG, PNG, or WebP image within the displayed file and pixel limits.
- Move the opacity slider while reviewing the checkerboard preview.
- Download the adjusted image as a PNG.
One focused transparency control
The slider scales the alpha channel of every decoded pixel from 0% fully transparent to 100% unchanged. Existing transparency is multiplied by the selected value, so a partially transparent source stays partially transparent.
PNG output and JPEG behavior
The result is always a PNG because PNG supports an alpha channel. JPEG input is decoded normally, then exported with the selected transparency; the original JPEG format cannot store that transparency. The output keeps the decoded dimensions and does not preserve EXIF, camera metadata, animation, color-profile chunks, or other source file structure.
Local browser processing
The image is selected, decoded, previewed, and encoded in your browser. Nothing is uploaded. Current browsers support the Canvas operations used here, though exact color handling and encoded file size can vary by browser and device.
よくある質問
あわせて知りたいこと
Can I make a JPEG transparent?
Yes. The JPEG is decoded in the browser and the result is exported as a PNG, which can store transparency.
Does 50% opacity remove existing transparency?
No. It scales the existing alpha values to half their decoded value.
Will the output keep my image metadata?
No. Canvas creates a new PNG and does not retain source metadata or animation.
Does this upload my image?
No. File decoding, previewing, and PNG export happen locally in your browser.