If this is still an issue, I can post the code I use to determine if mobile (or not).
Automated signup has been disabled for these forums. If you wish to register, please send an email to admin[at]punster[dot]me stating your preferred username.
Embedded images: Click on the 
Add image to post link below the message box. Your photo will be uploaded to the postimage website and then shared here via a thumbnail link. Click on the thumbnail for a larger view.
Private messages: There is no pop-up alert for new PMs on these forums, so you need to look out for the PM link (near the top right-hand corner of any forum page) becoming bold.