[imp] Attachement Size Final Verdict

[Sam Lalonde]

I have found a number of conflicing posts about this -- I'd like to try 
to get it cleared up.  What variables in php.ini control the maximum 
attachement size for IMP?

post_max_size ?
upload_max_filesize ?
memory_limit ?
other ??

What should the relationship be between these variables?  

For example, if I want the maximum allowable
attachment size to be 15 MB, what should I set the variables to?

thanks,
sam