Unfortunately I know absolutely nothing about programming. I will go ahead and tag @Rose, but I also know that she's super duper busy right now. 

Hopefully you can get some help @col-klink.

Hi @Col-Klink, first things first, are you uploading the image as the featured image in the post editor?

(Nice avatar, btw. )

@rose I'm able to make the uploaded images I want as headers fine in drafts. They always appear as the Featured Image there. But when I publish or preview the posts, the header image for the entire blog is what appears. It's mainly uploaded illustrations that don't seem to work. I can sometimes get it to work with uploaded photos (thought not always then either; I really don't get it) but illustrations would really be better for my blog. 

On my last post, I decided to bite the bullet and just have a photo be the header. It wasn't exactly what I wanted, but I figured when I shared the post on Facebook, it'd look more intriguing than my blog's normal header, which all my Facebook friends have seen. But when I shared it there, the image in the preview was neither of those, but instead the first image from the post proper.  

I think I might have found the problem. There's a minimum image requirement of 200 x 200 pixels for the preview on Facebook, and the header on your most recent post is 940 x 198. I'd try taking a look at the other posts and see if this makes sense based on which posts successfully previewed the image on Facebook and which ones didn't.

This page has more information on the ideal size for a featured image: https://wordpress.com/support/facebook-image-thumbnail/

Let me know if this does the trick!

I've been having irritations with Wordpress (R) since they changed their editor to "Gutenberg." It shreds links before my eyes. I enter it correctly and press UPDATE. Lo and behold, the link changes to something like kitten typing. Though that's unfair to kittens,

(I know WP doesn't like The Tube of You -- probably to avoid copyright quarrels -- but these links were both clean and varied.)

The "WP Classic Editor" is available for a financial transaction which I have not paid. Curiously, the classic editor sometimes pops up if I'm online for more than a few minutes. It's much less accident-prone. I miss it.

Rose-Tree's article explained the Facebook thing, I think, but it didn't explain why I can't get featured images to work. Does anyone have an explanation for that? I understand if no one does. It's just that it'd be nice.

BTW, does anyone know if there's a way to use different colored ink in WordPress? In my blog, I sometimes talk about the endings of movies because my blog is about adaptations and changes made to the end of a story are usually the most interesting. It'd be great if I could use a different colored ink for writing about sections that some of my readers might not want spoiled.

On some WP posts you can use < spoiler >your words here< / spoiler >. (Take out the spaces).

You would see a gray fog over the hidden text.

See also this HTML codes page ( https://www.web-source.net/html_codes_chart.htm )

Now most of the images in one series of posts I did (about the movie Les Misérables) have mysteriously disappeared. (And weirdly not all of them, just most, even though they all came from the same site.) "It was as if the gods themselves had first laughed, and then spat, in my face."  

EDIT: And now some of them are back, but not all of them. Apparently, it's a jetpack issue. I don't know what that means.

I've fixed my problem, I think. On a day when most of the images were there, I made an archived version of the page and then replaced all the images on the main one with the ones from that. I just hope it'll stay fixed.