It is great that you feel this way, nudes are an insane show of trust so you shouldn't take that lightly but I feel that you have misunderstood how the cloud works and backing up photos. These photos are not public, they are only available to you, you can make them public but even then people need the link to your page to see them so the odds anyone could have seen them even if you had them up for 2 years would be miniscule, 2h is just you being VERY paranoid. Sorry to say this but you talking to her about this only made her worry about something that was completely risk free.

But if both of you are so paranoid about having nude on the Internet then why not get a cheap Polaroid camera and do a little photo shoot, could be really fun.