Green bubbles are the ones you get from sending a message to a non-iPhone user, blue is from sending them to another iPhone user. (I say another, because this is iMessage which afaik only is on iPhone; the user themselves has an iPhone, though this is not relevant for the meme).
The joke is therefore that the other did, in fact cheat for the iPhone.
Left = the one you get messages from
Right = yourself
Green bubbles are the ones you get from sending a message to a non-iPhone user, blue is from sending them to another iPhone user. (I say another, because this is iMessage which afaik only is on iPhone; the user themselves has an iPhone, though this is not relevant for the meme).
The joke is therefore that the other did, in fact cheat for the iPhone.
Oh! I got the positions reversed. Thanks for explaining!