Why is it my pod touch 4th gen version 4.3.3 won't let me delete some pictures, says total gb is 6.5, and won't let me upgrade the firmware

My iPod touch is version 4.3.3 and recently I was thinking I'm sick of my iPods memory always being full so I can't take pictures. My memory has allowed at max 6.5 gb which is highly annoying so I started by trying to delete photos for room and I deleted about 300 and it didn't allow any more memory so I went to delete 41 more and they wouldn't delete for some reason. So I resorted to upgrading my I.o.s. But when I began downloading it onto my actual iPod an error popped up and it wouldn't let me.

So, my question is how do I get those 41 pictures to delete, make my max capacity of gigabytes higher than 6.5 when it's suppose to have 8, and lastly how can I get my iOS to upgrade?