In order to enable floppy-swapping, you must list all floppy images which is to appear in the floppy list. You can use floppy_image_0, floppy_image_1, floppy_image_2 up to (and including) floppy_image_19 for a total of 20 images.

floppy_image_0 = path/to/adf_or_ipf floppy_image_1 = path/to/adf_or_ipf floppy_image_2 = path/to/adf_or_ipf floppy_image_3 = path/to/adf_or_ipf floppy_image_4 = path/to/adf_or_ipf ... floppy_image_19 = path/to/adf_or_ipf