Sometimes when you insert new SIM cards tablets internet connection settings will be reset. Frequently the default APN is WAP. This often means that connection works, but is very slow, so photos and videos are pain to use.
So when you rent a device, enter your own SIM card then it is worth checking internet connection settings again.
So here is how to do it easily
Go to Settings->Cellular Data
Check that APN is what your network provider recommends (quite frequently it is just “internet”)
Go to Settings ->More->Mobile networks->Access Point Names
Check that there is an APN active that has your network providers recommended settings
Doing that will ensure that you will have optimal data speeds and best experience with photos and videos.
And while you are in the settings, turn your screen brightness to max and extend the screen timeout time. This will consume more battery but also improve game experience.