Mysterious network drives appear when opening photos on phone

Not sure if networking is the right place for this.

My boss is having a weird issue with his Win7 workstation. Whenever he connects his iPhone, browses to the iPhone drive listed in Explorer, and opens a photo from the phone, it causes mapped network drives to start appearing. One time I saw his screen and it had every single drive letter populated C thru Z!

We run a domain server in the office with workstations, and users log in to Active Directory, which runs a login script to map Z, Y, X and U drives. There shouldn't be anything else besides those, C, D optical drive, and a few more on machines with internal card reader drives.

Anyone ever seen this happen before?

Revisiting this issue, because I just saw it happen again on my boss's machine. He had a Word document open (Word 2013), went to Insert > Picture, navigated to his My Documents folder on the local machine, and inserted a JPEG image into the document. The program seemed to hang/think for a moment, and then suddenly in Windows Explorer, multiple network drives starting appearing, starting from the lowest available drive letter (like W) and working all the way up to "J". Each network drive was named the same, and it had the UNC network path of our OLD office server, which no longer exists on the network/domain.

Any ideas? Somehow something must be tied to the UNC path of that old server, but why it would create a bunch of network drives in Windows I have no idea.

In case anyone encounters this, apparently the issue was being caused by the Pictures Library having 49 different locations associated with it, most of which were old, outdated network locations on our previous server machine. I removed all but the local file locations, and it all seems to be good now.