iMessage is one benefit to having an iPhone for sure but the other person has to have iPhone as well of course, all my friends and family dont use text, we all use a messaging service(Whatsapp or Telegram(my fav), then it doesn't matter which phone &/or service you have, they both do downgrade video slightly but not nearly as much as MMS, if all else fails use google photos sharing as someone earlier stated and see the image in original quality.
BTW if google did come out with a iMessage like service still wouldn't solve the problem because then it would be android to android, and technically speaking they have this feature, it's called Hangouts, and its cross platform as well.