Other

I always wonder what "Other" is, in iTunes, when I look at my device (iPod touch 6) content. I don't have a lot of apps, I don't text or browse a lot, everything is pretty clean, but since a couple of days, I have almost 5GB of Other but I also have over 3000 photos on my iPod and it's only showing that it uses 40MB of space! So I believe that the "Other" not extra stuff but files that are not interpreted correctly and showed in the wrong category... Anyway, I only wanted to share this weird behavior