無料オンラインJPG→PNG変換
JPG画像を品質を失わずにPNG形式に変換します。
Frequently Asked Questions
Why would I convert a JPG to PNG?
PNG supports lossless compression and transparent backgrounds, making it better for logos, screenshots, and images with text or hard edges. If you're editing an image further, PNG preserves quality through multiple save cycles whereas JPEG degrades each time.
Does converting from JPG to PNG improve image quality?
No. Converting from JPEG to PNG stops further quality loss, but it cannot recover detail already lost during the original JPEG compression. If the JPEG looks fine, the PNG will look identical — just larger in file size.
Is my image uploaded to a server?
No. The conversion runs entirely in your browser using the Canvas API. Your file never leaves your device and nothing is stored or transmitted to any server.
Why is the PNG file larger than the original JPG?
JPEG uses lossy compression optimised for photos, achieving very small file sizes. PNG uses lossless compression, which preserves every pixel exactly — this results in larger files. PNG's advantage is quality retention and transparency support, not smaller size.
Can I convert multiple JPGs to PNG at once?
Currently the tool processes one image at a time. To batch convert, use each image in sequence — clear the previous result, drop the next file, and download. For large batches, a desktop tool like ImageMagick or XnConvert is more efficient.
Is the JPG→PNG変換 free to use?
Yes, the JPG→PNG変換 on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.
How does the JPG→PNG変換 work?
JPG画像を品質を失わずにPNG形式に変換します。 No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.
Do I need to install anything to use the JPG→PNG変換?
No installation needed. The JPG→PNG変換 runs entirely in your web browser on any device — desktop, tablet, or mobile.
Is my data safe when using the JPG→PNG変換?
Completely safe. The JPG→PNG変換 processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
Does the JPG→PNG変換 work offline?
After the page loads for the first time, the JPG→PNG変換 works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.
What image formats does the JPG→PNG変換 support?
The JPG→PNG変換 works with common image formats supported by your browser, including JPEG, PNG, WebP, and GIF. SVG support varies by tool. No format conversion plugin or driver is needed.
Does the JPG→PNG変換 work with large image files?
Yes. The JPG→PNG変換 processes files entirely in your browser using the Canvas API. Very large files (over 20 MB) may take a few extra seconds on older or lower-powered devices. Closing other tabs can free up memory for better performance.
Does the JPG→PNG変換 work on all browsers?
Yes. The JPG→PNG変換 is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.
How do I save or export my results from the JPG→PNG変換?
Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.