I don't remember any messages about a security token. Just in case it helps, here's where we discussed another mysterious-sounding error message.

By any chance are you trying to upload a picture from a site where you have to be logged in before you can see the picture? That could possibly explain the "security token" message when the picture site sees PC, not your own computer, requesting the picture.

If I were having a problem like this, I'd experiment with uploading pictures of different sizes (etc.) from different places (my own computer, other sites, etc.) until I found out exactly what I could and couldn't upload. Then I'd delete whatever I'd uploaded that I didn't want, and look for a way to upload the picture I did want.

So far it looks like the only way you can upload a picture to your album from another site is to have it on your computer first.