PNG vs JPEG: When to Use Which (and How to Convert Between Them) — WebConverter

PNG and JPEG are the two most common image formats on the web. They look similar in a browser window, but under the hood they work very differently. Choosing the wrong one can mean a bloated website, blurry text, or invisible transparency. Here is when to use each — and how to convert between them in seconds.

JPEG: Best for Photos

JPEG uses lossy compression. It analyses an image and discards visual information that the human eye is unlikely to notice. The result is dramatically smaller files — often 10× smaller than the uncompressed original.

Use JPEG when:

• The image is a photograph or contains smooth gradients
• You need the smallest possible file size for web pages, email, or social media
• The image does not require transparency
• Minor compression artefacts are acceptable

JPEG does not support transparency. If you save a PNG with a transparent background as JPEG, the transparent areas will become white (or black, depending on the tool).

PNG: Best for Graphics, Screenshots, and Transparency

PNG uses lossless compression. Every pixel is preserved exactly as it was — no information is ever discarded. PNG also supports an alpha channel for full transparency.

Use PNG when:

• The image contains text, icons, or sharp edges — JPEG compression creates visible artefacts around hard lines
• You need transparency for compositing on different backgrounds
• You are saving a screenshot or UI mockup where every pixel matters
• The image will be edited further — re-saving a JPEG repeatedly degrades quality, while PNG does not

Quick Comparison

When to Convert PNG to JPEG

If you have a photograph saved as PNG — for example, an export from a design tool or a camera app that defaults to PNG — converting it to JPEG can reduce the file size by 5–10× with negligible visible quality loss. This matters for web performance: smaller images mean faster page loads.

Convert your PNG to JPEG here — free, no upload needed.

When to Convert JPEG to PNG

If you need to add a transparent background to a photo, or if you want a lossless master copy for future editing, converting to PNG preserves the current state of the image without any further quality loss. Note that once JPEG artefacts are baked in, converting to PNG will not remove them — it simply stops further degradation.

Convert your JPEG to PNG here — free, no upload needed.

Other Formats Worth Knowing

Beyond PNG and JPEG, there are specialised formats for specific use cases:

• BMP — uncompressed Windows bitmap; perfect quality, very large files
• TGA — used in game engines and 3D pipelines for textures
• HDR and EXR — high dynamic range formats for photography and VFX
• KTX2 — GPU-ready texture format for real-time 3D and WebGPU

All of these are available on WebConverter.app, running entirely in your browser.