Are these invalid URLs some form of exploit?

I'm receiving spam emails that, looking at the email headers, appear to be coming from a variety of computers around the planet. They're always the same type of email that contains invalid URLs inside of HTML IMG tags. I've set Thunderbird to never show images, so these URLs are (I assume) never parsed. How can I tell if these URLs are in fact exploits? I have no idea who to ask about this kind of thing i.e. who is the authority on diagnosing spam emails.

Here are a few of those URLs. In case they actually are deliberately malformed URLs that contain exploit payloads... DON'T copy them into your browser !

Incidentally these emails are typically meant to appear as though they are coming from markers.tk domain email addresses, such as branchiform-cohomologies-glue@brama.markers.tk.

http://ift.tt/1CUpQbE
http://ift.tt/1AcLlV6     
http://ift.tt/1CUpRfr