OK, don't give up just yet, I now understand. First follow David Pogue's advice above as 542 MB for mail is a lot. Pogue wrote a very reliable book on the iPhone, The Missing Manual, so delete the account as he recommends and then add it again to free attachment space. Here it is again:
Delete email attachments. Files downloaded with your email take up a lot of space, too. The solution is to delete the email account (openSettings, then Mail, Contacts, Calendar, then the account name; scroll down and tap Delete Account) — and then add it again. Make sure you know your email passwords before you do this!
In the process, you’ll vaporize all the attachment files and message caches that you’ve ever downloaded and opened on your phone. When you add the account back again, those files will still be online, ready to download — but only when you need them. (This trick works for most account types — but not for POP3 accounts.)
Now to move pictures off your phone... Are these pictures in Camera Roll and are they pictures you took with the phone? (not pictures you synced from your computer to your phone I take it). If so don't use iTunes. If you have a PC go to the Windows File Manager, plug your phone into a USB port and you should see the phone listed there just like a camera. You can then copy the pictures to your PC and once you know for sure they are on the PC and only then, delete them from your phone (twice, you have to delete them from Camera Roll and then from Recently Deleted, click on Albums at bottom). If you are using a Mac then do the same but use Finder instead of Windows file Manager. Hope this time is the charm... 🙂
Oh, BTW, turn your Push back to ON.