unable to obtain destination image in IMAQ copy when placed in while Loop

[Kondle]

Hi,

I am trying to check whether the previous has current image or not after the loop. I do not find the current image stored in previous. I took an example code which acquires video from discussion form and would like to get a current frame and previous frame when using a while loop. Could anyone let me know, the mistake in the code. I am attaching the code.

[natasftw]

Attaching a picture is not attaching code.  Attach the vi if that's what you wish to do.

Previous will never be updated based on what you  show here.  Explain the thought process behind what you're trying to do, step by step