TahaFathalizadeh/Img2Webp ? reverse-engineered prompt

Build me a simple Persian web app that lets people convert images to WebP right in the browser. I want users to be able to drag and drop or click to upload multiple images, then convert them all at once with a quality slider and an option for lossless output. After conversion, show a side by side preview of the original and the WebP version, plus the file size before and after so people can see how much they saved. Each converted image should have its own download button.

Make it feel clean and fast, with a responsive layout that works on mobile and desktop, and support dark mode and light mode with the choice saved between visits. Keep it privacy friendly, so nothing gets uploaded anywhere and everything happens locally in the browser. Since this is for Persian speaking users, the text and layout should work well in Persian and feel natural in RTL. If you need to check current browser support details, look them up online.