can't transfer photos from chromebook to iphone 6s

I want to move some photos from my chromebook to my new iphone 6s. With my previous phone, a iphone 5c, all i had to do was plug in the USB, tell it to trust it, and then open up some windows in files manager then copy and paste / drag and drop them wherever. However, i can't seem to do that with my iphone 6s. I have updated to iOS 10.

I'll get a "do you want to allow this device to access your photos?" pop up, and i always click allow. Is this the new "do you trust this computer?"

I'd rather do this than use Google+, icloud, dropbox or google drive so please do not recommend those alternatives in place of a solution. Thanks for your help!