Broken blank screen- cant get iPhone to trust computer to recover pics

My iphone 4s which has a smashed, broken screen, is turned on and connected to my computer since I can hear the charging ping every 5 seconds or so, but since the screen is completely black, it won't allow me to let my phone trust the computer. I really want to recover pictures and unfortunately I didn't backup anything on iCloud and I'm not willing to get it repaired since i have a new phone, so is there any way i can get my phone to trust my computer or somehow recover my pics without paying???