PNG vs JPG: Which Format Should You Use?

> what_is_png

PNG (Portable Network Graphics) was introduced in 1996 as a patent-free replacement for GIF. It uses lossless compression — every pixel is stored exactly as it is. No data is discarded on save. This makes PNG ideal for images that need to be re-edited, archived, or displayed at perfect fidelity.

The defining feature of PNG is its 8-bit alpha channel transparency — each pixel can have a different level of transparency from fully opaque to fully transparent. This is essential for logos on colored backgrounds, UI elements, product images with transparent backgrounds, and sticker-style graphics.

The tradeoff: PNG files are large for photographs. A typical 12MP photo can be 8–20MB as PNG vs 2–4MB as JPG at 85% quality — with virtually no visible quality difference for the JPG. Using PNG for photos is a common mistake that bloats websites without any visual benefit.

> what_is_jpg

JPG (Joint Photographic Experts Group, also JPEG) was released in 1992 and remains the dominant format for photographs. It uses lossy compression — it analyzes the image and discards data that the human eye is least likely to notice, particularly fine textures in areas of uniform color.

The compression works by breaking the image into 8×8 pixel blocks and applying a Discrete Cosine Transform (DCT). At high quality settings (85–95%), the compression artifacts are invisible. At low settings (below 60%), you get visible blocking artifacts — square-shaped distortions especially visible around text and sharp edges.

JPG does not support transparency. Every pixel must have a color value — transparent areas become solid (usually white or black). For any image requiring a transparent background, JPG is not suitable.

> file_size_comparison

The file size difference between PNG and JPG depends heavily on image content:

For photographs: JPG wins decisively. A typical landscape photo at 300KB JPG (85% quality) would be 2–4MB as PNG — 7–13x larger with no visible quality difference to the human eye. This is why JPG is the standard format for all photography, from camera sensors to stock photo sites.

For graphics with flat colors: PNG is competitive. A logo with solid fills, sharp edges, and transparent areas will often compress to 20–80KB as PNG. The equivalent JPG adds compression artifacts around edges and cannot represent transparency at all.

For screenshots with text: PNG always wins. Text and interface elements have high-contrast edges that JPG compresses poorly. A screenshot that is 400KB as PNG becomes blurry and difficult to read as JPG at any reasonable quality setting.

> quality_and_artifacts

PNG is lossless — the saved file is a perfect representation of the original. Re-saving a PNG 100 times produces an identical result every time. There are no compression artifacts.

JPG degrades on every save. Open a JPG, make a small change, save it as JPG again, and the quality decreases. Do this 5–10 times and the degradation becomes visible. This is why professional workflows use PNG (or RAW) as the editing master and export JPG only as a final delivery format.

JPG's characteristic artifact is blockiness — 8×8 pixel patches that look like a grid of squares in areas of flat color near high-contrast edges. This is most visible in screenshots, diagrams, text, and logos saved as JPG. The artifact is not present at all in PNG.

> transparency_support

PNG supports full 8-bit alpha channel transparency — each pixel has an independent transparency value from 0 (fully transparent) to 255 (fully opaque). This allows smooth anti-aliased edges, semi-transparent shadows, and complex overlays.

JPG has no transparency support whatsoever. When you save a transparent image as JPG, the browser or application fills the transparent area with a background color — typically white. This makes JPG completely unsuitable for product images with white-removed backgrounds, logos, icons, overlays, and watermarks.

If you need transparency and smaller file size than PNG, WebP is the answer — it supports the same alpha-channel transparency as PNG while being 25–50% smaller.

> the_verdict

Use JPG when:

• The image is a photograph (landscape, portrait, product photo, food, travel)
• File size matters and there is no need for transparency
• The image will be shared via email, social media, or messaging apps
• Displaying user-uploaded photos on a website

Use PNG when:

• The image has a transparent background (logo, icon, sticker, overlay)
• The image contains text, sharp edges, or flat color areas (screenshots, diagrams, UI)
• You are editing the image and plan to re-save it multiple times
• Archiving original source files — PNG is lossless, making it a safe master format

For web delivery in 2025: consider WebP for both use cases. WebP is 25–34% smaller than JPG for photos, 26% smaller than PNG for graphics, and supports transparency — all with 97% browser support. Convert to WebP for the web, keep PNG as your source format.