That's one solution, but the reason of this is because if you solely use the "Show Picture" command, it will execute that file as quickly as it executes the script. Think about what would happen if a large image file is called upon as fast as your code. What that will do is create a lot of lag, and usually is what causes lag in any CBS.
The solution: Use a combination of show and move picture.
Frk Cndn: HP is 20 -Show Pic HP20 -Cycle -Move Pic 20 0.1 seconds (Don't choose halt other processes) -Frk Cndn: HP is not 20 -Break out of cycle -/End Cycle
The method above is one of the few cases where a cycle is better to use than a fork condition because it saves some coding. This is only one method of doing it, and probably isn't the best, but it will serve its purpose and should remove the lag. If it still persists, you may want to use labels, which will require a small extra bit of coding.