limit to number of files seen by ls?

[John Almberg]

I seem to have run into an odd problem...

A client has a directory with a big-ish number of jpgs... maybe 4000.  
Problem is, I can only see 2329 of them with ls, and I'm running into  
other problems, I think.

Question: Is there some limit to the number of files that a directory  
can contain? Or rather, is there some number where things like ls  
start working incorrectly?

-- John