The WD My Passport (4000GB) has only one port for a USB cable and therefore cannot be used with a mobile phone and/or camera. More specifications here: https://www.wdc.com/de-de....
Presumably the WD My Passport Wireless Pro can be paired with a mobile phone/camera. -> see: https://www.digitec.ch/de/s1/product/wd-my-passport-wireless-pro-4000gb-externe-festplatte-6199248. Exact product description on the manufacturer's website: https://www.wdc.com/de-de....

I tested it with my Huawei Mate 9 the HD WD My Passport (4000GB) does not even start as expected. Maybe something like this? ... -> WD My Passport Wireless Pro (4000GB) with a powerbank as support ....