How to change a thumbnail

That looks like a theme not from the WordPress Theme Directory. You would likely need to contact the theme provider’s support directly for a quick resolution.

There is no link to set a Featured Image down the right sidebar when creating a new blog post?

Yes there is. The only time it works is on older posts (from my original Blogger blog) that have no featured image yet. I can go in and pick one. But for all my new posts, it selects it and won’t let me change it. I’ve tried setting it before I publish and after, neither works. It’s allowing me to go through the process of picking or changing the thumbnail, then ignoring my choice.

I just hired someone to move me from Blogger to WordPress a few months ago. I encountered some problems along the way and would rather not have to contact the company that did it for me. However, I don’t understand a lot about WordPress, including the whole matter of “themes.” Do you know how I would go about finding out who the theme’s “provider” is?

Thanks for your help!

Usually the theme has a credit and a URL.
If you go into Appearance > Themes in the WordPress dashboard you should be able to see the Author.

I don’t know if this is your theme – but I found this reference online.
https://blogelina.com/2015/04/24/10-days-of-free-themes-day-ten-the-marianne/

Also – do you have a lot of plugins installed? Have you tried disabling them and then seeing if that feature works? If that is the issue – then re-enable them one at a time until you find the culprit.

Thanks, yes, the author is blogelina. I’ll check with them.

I don’t have a lot of plugins, but I will try disabling them if I don’t get results from bloglina.

Thanks so much!