What is the "trust" button on the iPhone?
I plugged my iPhone to my iMac to download new photos. This message appears on the iMac:
"This Mac has not yet been granted access to media on “(my) iPhone”. In order to import media to this Mac, tap “Trust” on “Verne's iPhone”. You may need to unlock the device first."
A: What does "unlock the device" mean? Is the device my iPhone? Or, is it Photo on my iPhone?
B: "Trust" does not appear on my iPhone. What is it and where is it?
iMac (21.5-inch Mid 2010), OS X Yosemite (10.10.1), screensaver photos