In a Jekyll file I have 

     <IMG SRC="/assets/images/

I would like to use the filename autocompletion shortcut to insert the rest of the filename, but this fails because of the leading slash. 

When I remove the leading slash, the completion works perfectly but I then I have to put it back in for the code to work.  

How can I tell vim to ignore the slash? 

Related question is [this one](https://vi.stackexchange.com/questions/3033/how-do-i-get-filename-completion-to-ignore-a-leading) but the solutions do not appear relevant.