Media loading problems

[ Moved to the Fixing WordPress sub-forum. ]

Having two media problems:
1. loading image from library to a Page suddenly requires multiple attempts.
2. JPG Image appears in the editor, but the post shows only the alt desc. in the posted page after multiple refreshes. Other images appear on same page with no problem.

Theme: Twenty Sixteen
New site, only 3 plugins Akismet, Jetpack, Limit Logins — Using Jetpack Photon

I am not a beginner, but not an IT expert either.