From my computer.
It's still a jpg file, so, yes, the forum accepts jpg's.
All I did to your pic was to resize it and save as to another filename. Your original file size is 2.4MB. It is not too big to post. I still don't have a fix, just a work-around.
iphoneX is not producing standard png and jpg files. You're gonna have to run them through your computer and resave them to png or jpg to post on the forum.