"Convert PNG" goes two ways depending on what you need.
Shrink a PNG: convert to JPG
A photo saved as PNG is huge. Open Convert to JPG to turn it into a much smaller JPG (transparency becomes white).
Need transparency: convert JPG to PNG
Going the other way, open Convert from JPG to export a PNG or WebP.
Tips
- Flat graphics and logos belong in PNG; photos belong in JPG/WebP.
- Learn the trade-offs in PNG vs JPG and PNG-8 vs PNG-24 vs PNG-32.