I am in doubt of my phone being a 16gb or 32 gb

Well, first an introduction of my question. I just got an iPhone 5s as a present from my mother. I googled the IMEI to know my storage limit because I the information on the phone (16gb) and what my mother was telling me (32gb) was not in accordance. On my search I also came across two different information. One saying my iPhone has a 16gb storage limit another that it is 32gb (images attached). When I got home I plugged it in to my itunes to check it and on there the information is that it is a 16gb iPhone. My question now is, how can I know for sure which information is correct? And if it is a 32gb where can I find the other 16gb?