The close up photos can be taken either with extension tubes or a macro lens. (neelywang.com)
A straw - like extension tube runs inside the bag from the sealed top to the bottom. (breastfeedingtoday-llli.org)
The 1.4 x teleconverter is designed for use with the new 250 mm F4 lens, while the two extension tubes allow for higher magnification ratios with any GF lens. (dpreview.com)