Access Image Control (Link to HTML w/ Variables)

I have a directory that contains employees of my company, and that directory houses a headshot for each employee.  The location of that headshot is http://www.website.com/employees/{USERID}.jpg where {USERID} is their actual ID number.

I have a table with UserIDs (Ex: 11598).  Is there a way to create a control on my form that I can use to link to that online directory by passing the UserID variable through?  

I'm thinking there would be a way to set the control source of an image to "http://www.website.com/employees/" & [UserID] & ".jpg"

I can't seem to find a way to pass any URLs through an image control.  There may not be a way to do it.  Any help is appreciated.

Thanks!