JPG vs PNG: which image format should you use?

The short answer

Use JPG for photographs and other images where a smaller file matters more than perfectly preserving every pixel. Use PNG for transparency, screenshots, logos, diagrams and graphics with sharp edges.

Compression and image quality

JPG uses lossy compression. It removes some visual information to reduce file size, and repeated saves can add artifacts around edges and fine detail.

PNG uses lossless compression. Saving a PNG does not introduce the same generational loss, although photographic PNGs are often much larger than equivalent JPGs.

Transparency and compatibility

PNG supports transparent and partially transparent pixels. JPG has no transparency channel, so transparent areas must be filled with a color when converting to JPG.

Both formats work in modern browsers and common software, but JPG remains the most universally accepted format for photographs.

Does JPG to PNG improve quality?

No. Conversion cannot restore detail that JPG compression already removed. A PNG copy can prevent additional lossy compression during later edits, but its starting quality is still the quality of the JPG source.

Worked decision: a product photo and a transparent logo

For a product photograph on a white page, first crop unused background and resize a copy to the intended display dimensions. Export JPG and PNG from that same source. Compare the label lettering and shadow edges at 100% zoom, then compare the downloaded byte sizes. Choose the smaller acceptable result; a PNG photograph is not automatically a better delivery file.

For a transparent logo, keep PNG when the background must show through. Inspect it against both white and dark backgrounds. A pale fringe can come from pixels blended against an old background; changing the file extension cannot repair those pixels. If a recipient requires JPG, choose the final background color before conversion.

A repeatable comparison you can do yourself

Keep dimensions constant when comparing formats. Otherwise a smaller image may appear to demonstrate better compression when it simply contains fewer pixels. Save each candidate from the original rather than converting JPG to PNG and back. Record format, width, height and file size alongside a note about the smallest readable text.

These are comparison steps, not benchmark results: the winning format depends on your actual image. Keep the source even after a delivery copy looks correct.