YES, ..... those I-phones store humungus size pictures (24" by 36") .... unless you change the "setting" on them.
My friend use to send me I-phone pictures via e-mail .... and they were so big I couldn't see them on my PC .... unless I saved them and then re-opened them with my photo program (MS Digital Image)
So reduce them down to ... standard e-mail size ... and they will upload. But remember if more than 1 picture ... the maximum upload per post is 3000KB