JPG is the most compatible photo format and usually the smallest. Here is how to convert to it.
Step 1: Open the converter
Open Convert to JPG and drop in a PNG, WebP, BMP or GIF.
Step 2: Download the JPG
Conversion runs locally; transparent areas are flattened onto a white background (JPG has no transparency).
When NOT to convert to JPG
Keep logos and graphics that need transparency as PNG or WebP. To go the other way, see how to convert to WebP. Background: PNG vs JPG and the PNG → JPG guide.