The folder is the document
Open one photo and the rest of the folder is there, in the order you'd number it: IMG_9 before IMG_10. Or by date or size, either way round.
- Opening a file opens its folder, starting at that file; opening a folder starts at its first image. Hidden files are left out.
- Natural name order: numbers inside names are counted, so
IMG_9comes beforeIMG_10. - By date or size, and reversed, from the palette, the right-click menu or Settings. The choice is remembered.
- Where you are: the header names the folder, and the sidebar says “4 of 8”.
- Open Recent (Ctrl+Shift+O): the last ten folders, found by name in the palette.
See The folder.