Thanks Sarah.
I read your entire explanation on this subject,This is very informative and helpful, Other things to consider in this , are the facts,that my iMac desktop is an early 2009 .It runs El Capitan,Henceforth it is restricted to limited technology ,
An important reason that my iMac desktop can't receive pictures in Photos is as follows;
On iPhone 11Pro,go to settings.Scroll down to camera.There you find Formats,click on that where you will find 2 settings.
High Efficiency and Most Compatible. Click on Most Compatible, to invoke this setting so that the high end iPhone 11Pro can now send pictures without any limitations on an iMac which software is El Capitan,Thank You Sarah for your help,which is greatly appreciated .Greetings: John Basso.