The preview and the export are worked out by the same code, so a page cannot look
one way here and come out another way in the PDF.
The card is the page
Each card draws the finished page: its shape, its margins, and the picture placed exactly where it will land. Change the page size or the margin and every card redraws, so you never save a file to find out what you asked for.
Your JPEGs go in untouched
A JPEG or PNG is embedded byte for byte, exactly as it came off the camera or the scanner. There is no second round of compression, so a tool meant only to stack pages cannot quietly cost you quality.
Phone photos come out upright
A phone stores a photo the way the sensor read it, with a tag saying which way up it belongs. A PDF cannot carry that tag, which is why photos land sideways in so many converters. Here the pixels themselves are turned, so upright on screen means upright in the file.
Fit to picture, or a real page size
Fit to picture gives every page the shape of its own picture: nothing cropped, no white bands. A4, Letter, Legal, A3 and A5 are there for when the result has to be printed or filed, with a margin in millimetres and your choice of fitting inside the page or filling it.
Order by dragging, or by name
Drag a card and a blue line shows where it will land. By Name reads the digits as numbers, so scan-2 comes before scan-10 - which is exactly where a plain alphabetical sort gets a scanned set wrong. By Date and Reverse Order are a click each.
Formats a PDF cannot carry
WebP, GIF and BMP are converted on the way in, keeping transparency where there is any, and the card says so underneath. Nothing is silently changed: a picture that was altered tells you it was altered.
