Chrome and many phones save screenshots as WebP. Photoshop, printers and older mail apps still want JPEG. Drop .webp files here, set quality, download .jpg.
Quality
90 is the default. 85 is usually enough for photos. Going below 70 shows blockiness on skies and gradients.
Transparency
JPEG cannot store alpha. The converter paints the picture onto white or black. White is right for documents and product shots. Black is better if the WebP was a UI on a dark theme.
Max width
Leave Original unless you need to send a 4000px screenshot through a form that caps dimensions. 1920 and 1280 are the usual web widths.
Up to 20 files. ZIP appears after two results. Conversion starts on drop; Convert again reapplies new settings.