Basically, the answer is that you need an auxiliary memory card, i.e. a microSD Card. This must be purchased separately. Once you have that in your phone, you can transfer stuff from your phone to it, and from it to your computer.
When I first plugged in my phone (before I put the microSD card in), it complained that I didn't have the right driver, so I went looking for a driver. There's no driver out there for the imprint, but apparently the driver for the Chocolate phone works. That can be found here:
Maybe you don't need any driver at all. I'm not sure whether, if you put the memory card in first, it won't ask you for a driver. If it doesn't, then good for you. Don't worry about it.
Other things:
Your phone must be set as a USB mass storage device (Settings > USB Mass Storage). I believe it is by default.
You can set pictures to be saved directly to the card (Memory > Save Options). Or you can copy pictures from the phone onto the card (go to the picture > Options > Move/Copy).
Once you plug your phone in, find it under My Computer and then copy the pictures from it to a folder in your computer like you copy/paste other files.
My MetroPCS store reps couldn't help me with this, but the LG phone reps told me what I needed.