The macro 
extracts existing V5 thumbnails from the selected models.
To start the makro you can either drop files from Explorer onto the icon ...
... or onto the form, if the macro has already been started.
The macro should also work from the command line or in a batch file, but it wasn't designed to.
The program acknowledges command line parameters(file and/or direcctory names) and also accepts files and directories dropped onto the form.
All CATParts, CATProjects and CATDrawings are accepted. The routine uses a blank to separate the command line parameters. Therefor blanks within the file or directory name will leed to an error.
When files or directories are dropped onto the form, blanks do not affect the outcome.
How it works
The program first checks the file ending, then looks for a V5-Header('V5_CFV2').
If both are OK, the JPeg signature is sought out by first looking for the string 'JFIF', and then the markers 'FF D8' and 'FF D9'.
The JPeg data lies between those two markers.
Then the data is read and saved to a file and displayed on the form.
'Escape' ends the macro.
Notes on Version 1.2
Limited the macro to only checking files with the appropriate ending(.CATPart, .CATProduct,.CATDrawing)
Notes on Version 1.2.1
I forgot to reset the debuwindowproc - parm when compiling V1.2. The error message does not appear any more now.