Unable to remove images from iphone 6
iTunes won't actually transfer pictures from your iPhone to your laptop. To do that, you will need to use the built-in Windows Image Capture program. It should open as an option when you plug your iPhone into your computer. After starting the program you can import the pictures from your iPhone. 

Here is Apple's official documentation on importing photos: https://support.apple.com/en-us/HT201302

These steps may be more concise:
http://www.digitaltrends.com/photography/best-ways-get-photos-iphone/