Does converting PDF to JPG lose quality?

Yes, JPG is a lossy format. At 90%+ quality settings, the loss is imperceptible for most uses. For zero quality loss, use PNG instead.

What DPI should I use?

72 DPI for screen/web, 150 DPI for general use, 300 DPI for printing. Higher DPI means larger files but sharper images.

You need to remove the password protection first. Most PDF tools cannot process encrypted files without the password.

Yes. The tool processes files entirely in your browser using JavaScript. No files are uploaded to any server.