So we have an old 6 running 12.4.1 we want to get a backup for so we can restore to a new phone. I’ve tried on a couple machines but I can’t get a clean backup. I get a nondescript “iTunes is unable to backup your phone” error. 

What are my options here? We really just need pics and iMessage restored. Can something like imaging do that? But the new phone will have 13 on it - can something like imaging work across versions?