Have no idea how to backup photos from iPhone 6 to flash drive, TunesGo is your best choice to help you.
TunesGo for iPhone 7/6S/6 Plus/SE/5S/5C/5 on Windows & Mac:
Key Features of TunesGo:
* Supports iPhone 7/SE/6S/6/6 Plus/5S/5C/5, iPod touch 6/5/4, iPad Pro, iPad air 2/1 and iPad mini 4/3/2/1;
* Transfer files from your iPhone 6 to you PC or iTunes;
* Transfer files between Apple devices;
* Convert multimedia files to formats supported by…