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PNG to JPG Converter

Convert PNG images to compact JPG format instantly. Reduce file size by up to 80% with adjustable quality. Choose background color for transparent areas.

ここに PNG ファイルをドロップ、またはクリックして選択

PNG ファイルに対応。最大 20 ファイル、各 20MB。

対応形式: PNG

ファイルサイズを小さくしやすい

写真系の PNG は JPG にすると大幅に軽くなることがあります。

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透過部分の背景色を選べる

JPG では透過を使えないため、白や黒、任意の色で自然に埋められます。

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画質を調整できる

用途に応じて容量と見た目のバランスを細かく調整できます。

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ローカル処理

変換はブラウザ内で完了し、画像は外部に送信されません。

Why PNG Files Are So Large

PNG uses lossless compression, meaning it preserves every single pixel without discarding any data. While this is great for quality, it results in significantly larger files compared to JPG. When you convert PNG to JPG, the lossy compression algorithm removes subtle visual information that the human eye rarely notices, achieving dramatic file size reduction.

Below is a real-world comparison showing the same 1920×1080 image saved in different formats and quality levels. Notice how JPG at 90% quality is nearly indistinguishable from the original PNG, yet takes up a fraction of the space.

PNG Original
1.2 MB
PNG-8 (256 colors)
280 KB
JPG 100%
450 KB
JPG 90%
180 KB
JPG 80%
120 KB

Based on a typical 1920×1080 photograph. Actual results vary by image content.

5 Scenarios Where You Need PNG to JPG

While PNG is excellent for graphics and transparency, there are many situations where converting PNG to JPG is the better choice. Here are the most common scenarios where switching to JPG saves time, storage, and bandwidth.

Email Attachments

Most email services limit attachments to 25MB. A batch of PNG screenshots can easily exceed this. Converting to JPG at 90% quality typically reduces total size by 70-80%, making email sharing effortless.

E-commerce Product Photos

Online marketplaces like Amazon, eBay, and Etsy have upload size limits. Product photos taken as PNG can be 5-10MB each. Converting to JPG keeps images under the limits while maintaining visual quality for buyers.

Social Media Sharing

Platforms like Instagram, Facebook, and Twitter re-compress uploaded images anyway. Starting with an optimized JPG gives you more control over the final quality and ensures faster uploads on mobile data.

Website Performance

Page speed directly impacts SEO rankings and user experience. Replacing PNG photos with JPG can cut image payload by 60-80%, improving Core Web Vitals scores. Google recommends using JPG for photographic content.

Storage Cleanup

Screenshots, camera exports, and design drafts in PNG format consume significant disk space. Batch converting to JPG can free up gigabytes of storage, especially for photographers and designers with large image libraries.

How to Convert PNG to JPG Online

Our PNG to JPG converter is designed to be fast and intuitive. The entire process runs in your browser — no uploads, no waiting for servers, no privacy concerns.

1

Upload PNG files

Drag and drop your PNG images or click to browse. Upload up to 20 files at once.

2

Choose quality & background color

Set JPG quality (60-100%) and pick a background color for transparent areas.

3

Download your JPG files

Get individual files or download everything as a single ZIP archive.

What Happens to Transparency?

JPG does not support transparency. When you convert PNG to JPG, all transparent areas in your image need to be filled with a solid color. By default, most tools use white — but our converter gives you full control.

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PNG with transparency

Checkerboard = transparent areas

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JPG with white background

Transparent areas filled with white

Tip: Our converter lets you choose the background color — white, black, or any custom color. If your PNG will be displayed on a dark website, choose black or a dark color to avoid visible white rectangles where transparency used to be.

Quality Settings: How to Choose

The quality slider controls how much compression is applied to your JPG output. Lower quality means smaller files but more visible artifacts. Here are our recommendations based on common use cases:

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Recommended

90%

Visually identical to the original. 60-70% smaller than PNG.

Best for: General purpose, web, presentations

Quick Share

80%

Minor quality loss visible only at zoom. 75-85% smaller.

Best for: Email, social media, messaging

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Maximum

100%

No additional compression. Still smaller than PNG.

Best for: Printing, archiving, professional use

PNG to JPG vs Image Compression: What's the Difference?

Format conversion and image compression are two different operations that are often confused. Converting PNG to JPG changes the image encoding, switching from lossless to lossy compression. This typically results in the largest size reduction because you are fundamentally changing how the data is stored.

Compressing a PNG, on the other hand, optimizes the existing lossless encoding by finding better compression patterns. The file stays in PNG format and maintains perfect quality, but the size reduction is more modest (typically 20-40%).

When to use which: If you don't need transparency and want the smallest possible file, convert to JPG. If you need to keep your image as PNG (for transparency, lossless editing, or pixel-perfect screenshots), use our PNG compressor instead. You can also compress the JPG output for even smaller files.

Batch Conversion Tips

  1. 1.Set quality and background color before batch converting — settings apply to all files.
  2. 2.Use consistent quality across a batch for uniform results.
  3. 3.Download as ZIP for convenience — one click gets all converted files.
  4. 4.Process up to 20 images at once on desktop, 10 on mobile.

Common Questions

Does converting PNG to JPG lose quality? Yes — JPG uses lossy compression, so some image data is discarded. However, at 90% quality the difference is virtually imperceptible to the human eye. The trade-off is a dramatic reduction in file size, typically 60-80% smaller than the original PNG.

Can I convert back to PNG later? You can convert a JPG to PNG at any time, but the quality lost during JPG compression cannot be recovered. The resulting PNG will be lossless going forward, but it will only preserve the JPG's quality level, not the original PNG's.

Why choose JPG over PNG? JPG is ideal when you don't need transparency and want small file sizes. It's the standard format for photographs, product images, and web content where loading speed matters more than pixel-perfect reproduction.

Is batch conversion free? Yes, completely free with no limits. Convert up to 20 PNG files to JPG at once. All processing happens in your browser — no server uploads, no accounts, no watermarks.

PNG から JPG への変換に関するよくある質問

はい。登録不要で、ウォーターマークもありません。

JPG は透過非対応のため、透明部分は背景色で塗りつぶされます。初期設定は白ですが変更できます。

はい。白、黒、またはカスタムカラーを選べます。

通常は 90% 前後がバランス良好です。容量優先なら 80% 前後も有効です。

JPG は非可逆形式なので多少の劣化はありますが、高画質設定なら多くの用途で十分自然です。

はい。デスクトップでは最大 20 件、モバイルでは最大 10 件まで対応します。

デスクトップでは 1 ファイル最大 20MB、モバイルでは最大 5MB です。

いいえ。処理はブラウザ内で行われます。

元ファイルはそのまま残りますが、JPG に変換した画像を再度 PNG にしても元の可逆状態には戻りません。

透過や可逆編集が必要なら PNG 圧縮、軽さ優先なら JPG 変換が向いています。

PNG から JPG への変換 - 無料オンラインツール | TinyImagePro