so here the deal: my jerk classmate changed my desktop background to a Penis , and ive tried to change it back but it will not let me , ive tried to change it though system preferences and via the internet but i think he has locked it as my back ground , how do i cahnge it back

so here the deal: my jerk classmate changed my desktop background to a Penis , and ive tried to change it back but it will not let me , ive tried to change it though system preferences and via the internet but i think he has locked it as my back ground , how do i cahnge it back

Right click on the image to bring up the contextual menu and then select get into. There will be a Locked check box in the General section.
OR
Click on the file in the Finder, choose Get Info from the File menu, and clear the Locked checkbox; if this box is grayed out, change the file's owner to yourself in the Ownership & Permissions section of the Get Info window.