iPhone 4S, iTunes and what is "Other?"

The thing I love most about the iPhone is that they are easy to use and easy to understand.  Everything is pretty intuitive, and if you mess around with it for just a short period, most people get the hang of what is what, and what does what.  You understand what it's capable of doing, and what it isn't capable of doing.  But every once in a while, there's something that an iPhone does that I can't figure out.  I ran into one such problem this morning while trying to free up some space on my phone.

I have a 16 GB iPhone, so space is limited.  I have nearly 6 GB of apps on there, and I've removed some of the bigger apps that were taking up space and I didn't need on there anymore (like Spotify, which I don't pay for so the app is kind of useless except for the radio feature, which is pretty sweet, but not sweet enough to take up as much room as the app takes up.)  But there was a mystery that I cannot solve.  According to my iTunes, when I hook up my phone, there is around 2.8 GB of space being taken up by "other."  I can't figure out what "other" is, and it's sort of driving me crazy.  Like I said, my phone is only 16 GB, so having nearly three of those precious gigs being taken up by a mystery "other" makes me want to do something about it.  

I searched around the internet, and I didn't really find anything, except someone saying that it's "album artwork, app artwork, things like that."  Really, though?  Almost three GB of artwork?  I deleted every song off my phone and it didn't budge the "other" section all that much (though it did go down slightly).  The fact that it moved makes me believe that this does have something to do with what "other" is.  But how do I significantly reduce the amount of space "other" is taking up?  

My other theory was that it was the weird data from my phone streaming my music library from iTunes Match.  That was actually my first theory, but after turning off iTunes Match and syncing my phone, it didn't do anything to "other."  No change. iTunes Match used to download every song you played from iCloud to your phone, but that was with the old iOS.  Now it doesn't download the music, or at least as far as I can tell.  It's really unclear to me.  I stream music from iTunes Match all the time, and when I turn Match off, the music isn't downloaded to my phone like it used to do.  That's why I thought that perhaps the "other" was this half-downloaded music in limbo.  No, I don't think it is, but who really knows?  I would have thought that Apple would have bragged somewhere that with iTunes Match you can stream you iTunes library without using up your phones space, but they haven't.  That's why I thought there was something up.  I don't know, it's just weird.

I also thought it might be Podcasts.  I am using the new Podcasts app, and I have a few podcasts that are unplayed and a few are kinda big.  I thought, since it's not technically in the music app anymore, maybe iTunes doesn't know how to categorize it.  After a bunch of trial and error, and deleting shit left and right, it made no impact on "other."  In fact, I came to the conclusion that my Podcasts are, in fact, recognized within the "music" section of the phone's usage.  So no, that's not it either.

This is where the internet can continue to help me.  Do you know how to reduce how much space "other" is taking up?  I beg you, let me know how I can reduce this burden!  If there is something simple I can do, or perhaps something I can do in the future to reduce adding to the "other" problem, that would be swell.