GIF Terminator

 In order to provide a synchronization for the termination of a  GIF image
 file,  a  GIF  decoder  will process the end of GIF mode when the
 character 0x3B hex or ';' is found after an image  has  been  processed.
 By  convention  the  decoding software will pause and wait for an action
 indicating that the user is ready to continue.  This may be  a  carriage
 return  entered  at  the  keyboard  or  a  mouse click.  For interactive
 applications this user action must  be  passed  on  to  the  host  as  a
 carriage  return  character  so  that the host application can continue.
 The decoding software will then typically leave graphics mode and resume
 any previous process.