Drop in one or several JPG photos and this places each one onto its own PDF page, with controls for page size, orientation, and margins so scanned documents or photographed pages come out looking like a real document rather than an oddly-cropped image dump. Drag to reorder the photos before you export, since PDF page order follows whatever order they're arranged in here.
Yes — drag and drop the thumbnails into the order you want, and the resulting PDF's pages will follow that exact sequence.
The tool places your JPGs into the PDF without additional lossy recompression beyond what your JPG already had, so visual quality is preserved — the main thing to watch is that fitting a very high-resolution photo onto a small page size will scale it down visually, even though the embedded data isn't degraded.
Standard sizes like A4 and Letter are supported, along with both portrait and landscape orientation, so you can match whatever paper size your document is meant to be viewed or printed on.