Allow F-Secure Anti-Virus for Mac to remove the relevant files.
Trojan-Dropper:OSX/Revir.B drops a JPG file in the /tmp folder, then opens it to distract the user from noticing any other ongoing activity.
Screenshot of a JPG file dropped by Trojan-Dropper:OSX/Revir.B.
Note that the JPG file in the screenshot above uses the name 'trojan.jpg'. The JPG file will actually use the same name as the trojan-dropper's binary file.
In the background, the malware will drop and execute a backdoor program (detected as Backdoor:OSX/Imuler.A):