Hi Jeremy,
I don't find the 50-degree temperature to cause any problems with painting. I have used Tamiya spray cans, Tamiya acrylics through my airbrush and a few other paints, and they all go down fine and dry just fine as well. They take longer to dry on a humid cold day than a dry hot day, but nothing to be worried about.
As for the photo posting, it looks like you got the photo posted, but to answer the question, no, there is no delay. When you click the image button and add the source code from your photo, it should show immediately in the desired spot even before you hit the post button.
-BD-