Is your iPhone 6 set to back up automatically? If yes, your data has been backed up to iCloud when your iPhone 6 was charging and connecting to wifi.
If no, and iTunes can not access your iPhone. According to your condition, you may need a third party program for help.
You can read this article about how to recover deleted photos from iPhone.
Data recovery software can recover many types of files like videos, photos, music, messages and so on.
Step 1: Download and install it, connect your iPhone to computer and select the types of files you want to recover.
Step 2: Wait for the scanning completed.
Step 3: Scanning completed. Preview files and pick up want you need to restore!
Hope my answer help!