This is the case when the user has not passed 'data' or 'reupload' to the --opt parameter, so you do nothing, right?  It would be better to test for this right after reading the command line parameters and quit with an error.  For example, if I accidentally did this:

  updateThumbnail.php --opt repload

the code would do nothing here, but on line 112 it would set $changed to 1 and at scripts end it would report success for all the videos and I may never realize that I had passed the wrong argument.