Access 03: Hyperlinked jpgs open in IE, not Irfanview.

In my collectibles database, the last column is a hyperlink to
"C:\inventorypix", which is a folder of .jpg's. If I double click on a .jpg
in the folder, it opens in Irfanview, and it *used* to do that when I clicked
the hyperlink in Access.
Unfortuately, several keys were held down together (Very long story), and
now my .jpg links open in Internet Explorer. ACK!
What did I do, and how do I undo it; IE is great for many things, but it's
not the optimum in picture viewers.
Thank you for your help,
Rob