If I understand your desire, it's to be able to convert a graphical image (bit map or screen photo, for example) into a functional block of LabView code, with all of the wire work done, etc. This is a task approximately equivalent to performing optical character recognition.
In the case of a non-system subvi, unless that subvi is loaded, so that it's graphical representation can be recognized by comparing the bit-map image for the subvi on the photo with the available vi's.
Another difficult problem to solve is when the bit-map has been scaled up or down, such that there's a pixel count mismatch between the VI iconic bitmap and the photographic bitmap you wish to import into your code diagram.
And if you try to do recognition on objects that have h
ad their RGB color representations changed, as can happen when JPG compression or other compression forms are used that reduce to total number of colors saved, that challenges the object recognition further.
Also, what you're interested in having is only of value to Labview programmers, so there's not a very large market for such a tool to be sold to - unlike bitmaps of scanned text to ASCII or wordprocessor applications - traditional OCR software.
All this ins't to say it can't be done, but that it's difficult, and for the person or company that undertakes it, the sales potential is limited.
Regards,
Bob Donnell