In order to fix the issue, press the Alt + Ctrl + Delete key combination, open the Task Manager and close all the programs (photo viewers, cataloging tools) that may use your pictures. If it doesn't work, right-click on the file you want to rename, select Properties and click the Security tab. Press the Edit button, check all the boxes bellow the Allow option and click OK. If the problem persists, try to temporarily disable your antivirus program and launch the program using the Run as Administrator option.