如何在.NET中创建长度为12个字符的随机文件夹名称

I would like to create random folder names on my website to store images and their thumbnails, but instead of using the full version of a generated guid, i was thinking about using just part of it, maybe just the first 8 characters and possibly base64 encode it. i am worried about possible collisions though. I would like to create random folder names on m