Apple tries to adjust the iOS App default settings to make the most of speed and storage space. One way they do this is to set iMessage images to what they call Low-Quality Mode. I think this is fine for everyday use, but occasionally, you have a remarkable picture that can only be appreciated in Full Quality. Maybe you are showing off your photography talents or taking a photo for another person. If you wish to send photos in Full Quality mode, then read on for how to do that.
Full Quality Images
You switch to Full Quality mode in the Settings area. Once in Settings, scroll down and tap on Messages.
There are tons of settings in the iMessage App.
You have to scroll down to the bottom of this window until you find “Low-Quality Image Mode”.
Next, just toggle that setting off.
Once that setting is off, you are good to go. The images you send to people will be higher quality. Keep in mind this will take up more space on your iPhone. If you are concerned about that, then toggle this setting back to Low-Quality mode when you are finished.
The iPhone takes good quality photos. If you wish you send high-quality photos using the iMessage App, you can do so.