PNG vs JPG: When to Use Each Format
Most people save images in whatever format their phone or design tool picks by default. That works until it doesn't — until you're staring at a blurry logo, a file that won't upload, or a product photo that's 8 MB for no obvious reason.
The choice between PNG and JPG is one of the most common decisions in digital work. Getting it right costs you five seconds. Getting it wrong costs you quality, compatibility, or storage.
The core difference
JPG uses lossy compression. Every save permanently discards some image data to shrink the file. For photographs — millions of subtly different colours blending into each other — this loss is usually invisible. A sunset photo saved as a high-quality JPG looks identical to the original at 1/10th the file size.
For text, logos, or sharp geometric shapes, the story is different. JPG compression creates visible artefacts — blurry edges, colour halos, blocky patterns — around high-contrast areas. A screenshot of a spreadsheet saved as JPG often looks noticeably worse than the original.
PNG uses lossless compression. Every pixel is stored exactly. A PNG saved and resaved a thousand times is bit-for-bit identical to the original. It also supports transparency — pixels can be partially or fully transparent — which is essential for logos and icons that need to sit cleanly on different backgrounds.
The size tradeoff is significant. A 3000×2000 photograph might be 400 KB as a high-quality JPG and 4 MB as a PNG. For photographic content, PNG's size penalty isn't worth it. For a logo with flat colours and sharp edges, PNG's quality preservation is worth the extra kilobytes.
Use PNG when
- You need transparency. Logos, icons, stickers, and overlays that sit on different backgrounds all need alpha channel support. JPG cannot do transparency — it uses a white or solid background.
- The image contains text or sharp lines. Screenshots, diagrams, slide exports, code snippets. JPG compression makes these look soft and blocky. PNG keeps them crisp.
- You'll edit the file again. Each JPG re-save adds another round of quality loss. If you're going to crop, resize, or adjust the image, keep it as PNG until the final export.
- Exact colour accuracy matters. Medical imaging, print-ready artwork, technical diagrams where colour changes carry meaning.
Use JPG when
- The image is a photograph. Natural scenes, portraits, food, products — JPG handles continuous colour gradients extremely well at dramatically smaller file sizes.
- File size matters. Social media, email attachments, web images, upload forms with size limits. A 400 KB JPG loads faster than a 4 MB PNG and often looks identical.
- Transparency isn't needed. If the image goes on a solid background, JPG's lack of alpha channel doesn't matter.
- Maximum compatibility is required. JPG is accepted everywhere — every platform, form, and application. Some older systems have inconsistent PNG support.
On the web
Both formats are supported everywhere, but there's a third option worth knowing: WebP. It achieves JPG-quality photo compression at 25–35% smaller file sizes, and also supports transparency like PNG. Modern browsers support it fully.
The practical web rule: use the smallest file that still looks good. A 400 KB homepage image loads noticeably slower than a 60 KB one on mobile, especially on slower connections.
Converting between them
When you convert JPG to PNG, the file gets bigger but doesn't gain quality — the lossy data is already baked in. Converting PNG to JPG permanently discards quality, so keep your original PNG if you might need it later.