OSXX, thanks for your tip. I email this message to my son that I found after a quick search:
"When you email photos with the iPhone, it gives you the option to choose which size you want to send. Tap your "Photos" app icon to access your photo library, then tap the small arrow in the bottom-left corner. Select the photos you want to share, then tap "Email." This is when your iPhone gives you a choice between small, medium, large and actual size. Choose "Actual Size" to send the photo in full resolution."