I found this too, the reason being I copied the mirc.exe to another mirc directory with an older mirc (to replace it), and forgot to replace the mirc.hlp, meaning the help file would point to the wrong things (and in some cases pop up a "no such topic" error).
You'll you have to upload your locally stored image to a webserver and link from that. There are plently of free hosting web servers out there, although many of them have leeching protection.