This is a nice idea.
In the mean time, here are two workarounds, either of which might be easy enough:
1) Right-click > Locate > On Disk (external) will open the containing folder, selecting the image. Then Shift right-click to find the Copy as path menu item.
2) Create a new Send To command. Tools > Send to > Send To (External) > Add /Edit Programs... In the dialog, click Add, and then set the Name to Show in IE, and then the Program Path select Browse and browse to either:
C:\Program Files\Internet Explorer
C:\Program Files (x86)\Internet Explorer
Select iexplore.exe and leave the Parameters as "[Filename]". Don't select Use a copy.
Ok and exit out of the dialogs. Now, you can right-click an image, Send To > Send To (External) > Show in IE and it will be opened in IE, where the path is available in the URL bar. On subsequent runs, the Show in IE will appear at the top of the Send To list.