IMAGECLIP lsp file
That's a command, not an AutoLisp routine. Whatever drives it would be embedded in the core software, not in a routine you could edit, any more than you can get at what drives the LINE command.
If you describe what you [presumably] want to be different about it, someone may have an idea how to accomplish it.
Kent Cooper, AIA 
@Kent1Cooperwrote:That's a command, not an AutoLisp routine. Whatever drives it would be embedded in the core software, not in a routine you could edit, any more than you can get at what drives the LINE command.
@Kent1Cooper in this case it appears you are correct. You likely know this but to clarify, some "commands" are saved as lisp routines. Saveall, MVsetup, Burst, for instance. It seems mostly like Express tool commands have actual lisp files, but some others as well. As you said though, I found no lisp file for imageclip.
@Shneuph wrote:
@Kent1Cooper in this case it appears you are correct. You likely know this but to clarify, some "commands" are saved as lisp routines. Saveall, MVsetup, Burst, for instance. It seems mostly like Express tool commands have actual lisp files, but some others as well. As you said though, I found no lisp file for imageclip.
If you put a command or function name into the Search window in Help, it comes back in the list of Search returns with its name followed by something in parentheses identifying what category it's in. If that something is (Express Tool), as it is with [for example] BURST, it even tells you what file it's defined in. If that something is (Command), as it is with IMAGECLIP, then you won't be able to get at it.
Kent Cooper, AIA
@Anonymous wrote:
What I want to do differently is highlight all images that need to be clipped and then pick the polyline for each image to be clipped to without having to re-enter the entire command in every time.
That sounds like a challenge to automate, but might be possible. A routine could perhaps highlight the images one at a time so you can pick the Polyline for each, assuming the Polylines won't be hidden behind the images [since presumably they're smaller]. Or rather than selecting all Images at once first, it could ask you to select by window an Image and its relevant Polyline, repeatedly as long as you keep picking such pairs, in which case it wouldn't matter whether the Polylines are hidden behind. But that may depend on your circumstances -- not too much overlap, etc.
Kent Cooper, AIA