Locking and Unlocking Files and Folders
Though Subversion integration allows you to successfully modify and merge files changed by different team members, sometimes it makes sense to lock files (for example, images) to avoid overwriting changes.
Lock a file
Unlock a file
Select the file you want to unlock, or open it in the editor.
Select VCS | Subversion | Unlock from the main menu, or Subversion | Unlock from the context menu of the selection.
To forcibly break a lock set by somebody else, select the Steal Existing Lock checkbox.