I have always believed that the first step of learning something is to learn what it is called. This is a tiny step, but a good beginning. In the world of computers, names are often confusing, especially if they are used as an abbreviation. "De-mystifying" names in the digital world is something I like to do and I am always happy to share what I have learned with my clients and my students.
JPEG stands for "Joint Photographers Expert Group". This group created the compression standard for this file type, which is used for images.
MPEG stands for "Motion Picture Experts Group". This format can be used for both audio and video (it's the type of file on your iPod), and since it has "outgrown" it's name, it's probably best to use the abbreviation.
By the way, iPod stands for "Internet Pod". When the internet was new, back in the 90s, the Apple Macintosh computer company introduced a small, inexpensive computer that was designed to be used mostly for connecting to the internet. I was called the "iMac" (see picture). This product was so successful that it helped to revive the company, and they started naming different products with the "i" (the iPhone, etc.).
My personal favorite has always been "TWAIN", which stands for "Technology Without An Interesting Name". Well, you gotta call it something!