Okay. I know what's going on there. You are correct this is spam that does not originate from you. The issue is that it is not your gmail address that is being forged, but your other address that forwards to gmail. You have also configured your forwarding server as a valid mail originator for your address in SPF. So the mail looks completely legitimate to gmail: it arrives at gmail from a server that you have configured as a valid server to send from your email address, therefore gmail thinks it really is from your email address.
If you control your own domain and you use gmail's smtp server for outgoing mail, you should remove the SPF entry that marks the forwarding server (hostmonster.com) as a valid originator for your domain. Then gmail will be able to figure out that this is forged. This will likely cause gmail to put this stuff properly in Spam and to avoid showing you the images.
