What do you mean of storing JPG image in a file?
If you want to load JPG (in Windows app) using C, you could take a look at this old thread:
How to display a JPG file using BitBlt?[
^]
Or you could use some JPG lib like:
this[
^]
But to me, it's a lot easier to use Listview and then send
LVM_SETBKIMAGE[
^] (I believe there're at least 2 of my apps using this :))