To create a PDF:

1. Drag and drop images into your desired order.
2. Optional: If you want to group any images onto a single page of the exported PDF, hover over an image, and choose a grouping option. If no grouping options are chosen, each image will exist on its own page within the PDF.
3. Once you're satisfied with the order of images, and their grouping (if any), click the "PDF" option in the header.

Note: dragging an image into or out-of an existing group will ungroup the images within the group.