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NJHTools

Image Format Converter

Convert images between PNG, JPEG, and WebP with an adjustable quality slider and instant before/after size comparison. Batch convert several files at once — every conversion runs 100% in your browser, nothing is uploaded.

Output Format
90%

Lower quality means smaller files (JPEG & WebP).

Drag images here, or click to upload

PNG, JPEG, WebP, GIF and more — all processing happens in your browser, nothing is uploaded.

How to convert image formats

  1. Drag your images onto the drop zone or click to select files — PNG, JPEG, WebP, GIF and more are accepted, and you can add several at once.
  2. Choose an output format — PNG (lossless), JPEG, or WebP.
  3. For JPEG and WebP, adjust the quality slider to balance size and detail.
  4. Compare the before/after sizes, then click Download on a single image or Download All to save every converted file (each downloads individually — no ZIP needed).

Each image is decoded and re-encoded entirely in your browser with the Canvas API — no file is ever uploaded, tracked, or stored. Converting to WebP usually produces the smallest files at the same visual quality.

Frequently Asked Questions

Are my images uploaded to a server?↓

No. Every image is decoded and re-encoded entirely in your browser using the Canvas API. Your files never leave your device and are never uploaded, tracked, or stored.

Can I convert multiple images at once?↓

Yes. Drop or select several files and the converter processes them all in one batch, showing each as its own card with before/after sizes. You can download each result individually or use Download All to save them one after another — no ZIP file or extra software needed, and nothing is uploaded.

Which format produces the smallest file?↓

WebP usually produces the smallest files at the same visual quality, often noticeably smaller than JPEG and far smaller than PNG for photos. PNG is best when you need lossless quality or transparency.

Does converting to JPEG remove transparency?↓

Yes. JPEG does not support an alpha channel, so transparent areas are filled with white when you convert to JPEG. Use PNG or WebP if you need to preserve transparency.

What input formats can I convert?↓

You can load any image your browser can decode, including PNG, JPEG, WebP, GIF, and BMP, and export it to PNG, JPEG, or WebP.

Is this image converter free?↓

Yes, it is completely free with no signup or account required, and no watermark is added to your images.

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