Mi2 broken screen, any way to retrieve photos?
You could try and boot the phone into recovery or bootloader mode (using either adb or just turning it off then holding the power and volume up or down keys as it's booting back up) and then use the adb pull /sdcard/DCIM/* C:/camera_backup command (as LyricWulf suggested) to backup all the photos from the phone.

Good luck getting those photos :)