Since those are browser based applications you should be able to upload your pictures just fine.
Before answering your question I decided to try my Picassa account. It opens via the Web Browser but when I select Jpeg files for upload the service returns a message saying they are not a supported file type. This is not true as they are Jpegs, however, the Picassa service must not recognize the Nook Tablet's file system. I will work with this a bit but you may or may not beable to upload images from your Nook to an on-line service. I can view my Picassa folders and pictures on the Nook so that works for sharing with friends and family.