32GB of flash memory is actually ~29.8GB. Conversion here.
Marketed gigabyte is 1,000,000,000 bytes, but the actual size is 1,074,000,000 bytes. Android partitions the storage just like Linux, so the storage available to the end user is actually smaller than the total. These partition sizes differ based on the phone, so there might be some issues if you try to re-partition it to open up more space. If you want more room for media, best bet is to get a USB OTG cable and a small, high capacity USB drive, or some companies sell drives similar to this.
Sorry, but someone more versed in the LG G2 in particular would have to chime in to give you the specifics. You could try asking on the general G2 Q&A forums.
Samsung Rant > LG Optimus V > HTC Sensation 4G > LG G2 D801