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PNG vs JPG: Which Image Format Should You Use?

A practical comparison of PNG and JPG covering compression, transparency, quality loss, and which one to pick for the web.

7 min read Last updated 2026-07-19 Luis Avila

PNG vs JPG: Which Image Format Should You Use? explains PNG and JPEG image formats from the concepts that matter most to the decisions you make in practice. It focuses on how the technology works, where it fits, the tradeoffs to check, and how to avoid results that look correct but fail in a real workflow.

What will this guide cover?

The essential difference
How does compression affect an image?
Choose PNG for
Choose JPEG for
Practical comparison
Web and workflow practices
Common mistakes and limits

The essential difference

PNG uses lossless compression and supports transparency, while JPEG uses lossy compression designed for photographs and continuous-tone images. PNG preserves exact pixel values but often creates larger files. JPEG discards visual detail to achieve much smaller files, especially for photos.

How does compression affect an image?

JPEG divides an image into blocks and reduces fine color and brightness detail according to a quality setting. Repeated saves can add visible artifacts around edges. PNG compresses repeated pixel patterns without changing the decoded pixels, which preserves text, icons, and screenshots more reliably.

Choose PNG for

Use PNG for interface screenshots, diagrams, logos with transparency, pixel art, and images containing sharp text or flat colors. It is also appropriate when exact pixels must survive editing. Large photographic PNG files are usually inefficient for web delivery.

Choose JPEG for

Use JPEG for photographs, realistic backgrounds, scans, and other images with many subtle color changes when transparency is not needed. Export from the original source at the final dimensions and select the lowest quality that remains visually acceptable at normal viewing size.

Practical comparison

A 1600×900 product photo may shrink dramatically as JPEG with little visible difference, while the same photo as PNG may remain several times larger. A screenshot of code or a chart often looks cleaner as PNG because JPEG can blur small text and create halos around high-contrast lines.

Web and workflow practices

Keep an editable master file and generate delivery formats from it. Resize before compression, remove unnecessary metadata, and use responsive image dimensions. Modern formats such as WebP or AVIF may outperform both, but PNG and JPEG remain useful fallbacks with broad compatibility.

Common mistakes and limits

Changing a .jpg extension to .png does not convert the encoding. Saving an existing JPEG as PNG stops further lossy compression but cannot restore discarded detail. PNG transparency can increase file size, and JPEG does not support alpha transparency. Always judge quality at the actual display size.

Frequently Asked Questions

JPEG is usually better for photographs because its lossy compression reduces file size efficiently in images with continuous tones and natural texture.

PNG is usually better for screenshots, interface graphics, diagrams, and logos because it preserves sharp edges and flat colors without compression artifacts.

Standard JPEG does not support an alpha channel. Use PNG, WebP, AVIF, or SVG when transparency is required.

PNG preserves pixels losslessly, but that does not make it the best delivery format for every image. A photographic PNG can be many times larger than a visually similar JPEG.

The PNG preserves the already-compressed pixels but cannot restore detail removed by JPEG compression. The resulting file is often larger without improving quality.

JPEG compression groups and approximates color detail, creating ringing and block artifacts around sharp high-contrast edges. PNG is more suitable for small text and UI captures.

Yes. Each lossy re-encoding can introduce additional artifacts. Keep a lossless master or original source and export JPEG only for final delivery.

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