I can't think of anything else to try so wanted to know if you had any other suggestions.
Using the Habitat Theme.
Created a post, uploaded the image, as a featured image to the post's Gallery, put a description in so it it would appear as a caption on the image, nothing appears.
I created another post, uploaded the image again, then went to the Media library & changed the Title & added a description, still it doesn't appear.
I tried to add a description to an image on another post - that worked. I also tried adding another image to this post
I deleted the image & then changed it's name & then uploaded that, still not working..
I just can't figure out why for this one image it doesn't seem to want to work??