iphone photo icon disappeared

It's a pre-installed app and therefore cannot be deleted so you may have inadvertently moved it onto a screen or into a folder. Check all screens and folders and do a search in Spotlight, it will tell you if the app it still on your iPhone but unfortunately not where it is. If you find it on one or your screens or in a folder, press the icon until it wiggles and then drag it back to where you want it. Alternatively you can reset your home screen in Settings>General>Reset>Reset Home Screen Layout.

check to make sure you don't have restrictions turned on blocking the camera

if that's fine then do a hard reset, hold lock button and home together (ingore the power off slider) and don't let go until you see the apple logo appear, once you see it then you can release both buttons

thanks to you iman. I had some icons disappeared and tried a hard reset and the icons appeared back as magic.

I'd like to thank you as well iMan87. The hard reset restored the missing photos icon and a few others that faded off into the ether.

Cheers.

Thank you so much. This really helped me. Photo icon restored, phew!