Old iPhone not enough storage to update?

I got my phone in February 2012, so it's pretty old. It's an iPhone 4. Revert I haven't wen able to charge it because it's running such an old version of iOS that when I plug it in it says "charging not supported with this accessory." I would download the latest iOS but it needs 3gB of storage to install and I only have 200 mB free as my phone only holds 6gB total. If I delete all my photos, download the later iOS, will my original storag be back or will I never have room for photos in my phone again?

For Starters It's been about a year It's not that old. I think you may just have to delete stuff and you can update it.

Dont update your IOS using your phone. You better use itunes to update your IOS.

If it is a big update then you will not have room for the photos and you cannot get them back.