What is required to make card art load?

Still struggling with getting card art loaded in for several sets.
The frustrating part is that I have artwork in .jpg form, but I can't seem to figure out how to get the program to recognize it. I've tried countless combinations of directories and filenames, taking inspiration from existing working art in other folders.
Could someone please inform on what it takes for art files to be recognized?
Thanks in advance!
The frustrating part is that I have artwork in .jpg form, but I can't seem to figure out how to get the program to recognize it. I've tried countless combinations of directories and filenames, taking inspiration from existing working art in other folders.
Could someone please inform on what it takes for art files to be recognized?
Thanks in advance!