I think the best option for your pictures is going to be a cloud service. I use Dropbox to backup all my pictures. You can also do this with Picasa or Photobucket. Photobucket resizes pictures though.

 

1. Check out Dropbox. You may also want Dropsync to use with it.

2. Yes, you can still use it on WiFi.

 

The Droid should work fine as a wifi only device.

 

If you have the USB cable, you can connect the phone to the computer to copy over your pictures and videos.

 

Or pull out the sd card and stick that in your computer.

 

You can also checkout Box, it's just like dropbox.

I signed up for box when they were offering a free 50GB account, don't know when that expires though.

But for that large of a transfer I'd say plug in the phone and drag and drop.