The short answer
Use WebP for modern websites when smaller files and page speed matter. Use JPG when broad compatibility, marketplace uploads, email attachments, or older apps matter more.
When WebP wins
WebP can make website images lighter while keeping good visual quality. It is a strong choice for blogs, ecommerce product pages, landing pages, and image-heavy sites.
When JPG wins
JPG is safer when a form, marketplace, CMS, or recipient expects a classic photo format. Convert WebP to JPG when a file will not upload or open.