No, this camera does not support wifi connection. 

The diameter of the biggest part, namely the camera head, is 23mm/0.9in. 

You can view photos and videos from this WiFi trail camera without removing it from the mount. And you can set the camera in the APP. This is very useful for cameras mounted in high places or hard-to-reach places. 

1.If the camera's current Wi-Fi and the Wi-Fi you want to switch can be connected at the same time, you can switch Wi-Fi directly by selecting Wi-Fi network in the settings interface. 2.When the camera is disconnected from the current WiFi, the app will show "Device disconnected". Click Troubleshoot to connect directly to a different wireless network. Or remove the camera from Tuya Smart and then connect the camera to the Wi-Fi you want to switch to. 

I don't know the exact size but it even fits 12-13 year old kids.