please help me remove random thumbnails from my blog page?

I find it enraging, and absolutely inappropriate that wordpress is putting random thumbnails next to my blog posts and I cannot remove them. How is it that I am paying for a web customization that puts teddy bears with hearts on them and photos of ferris wheels all over my project blog page?

https://voices4mekongforests.org/blog/

this is my page. Look, there are pigeons too! none of these images are in my media, and absolutely none are listed in the thumbnail column of my posts either – in fact, some posts have their own thumbnails, but I would rather remove thumbnails entirely, rather that re-assign thumbnails to 50 posts. The point is the text, not the images.

I have run the following plug-ins, to no avail:

thumbnail cleaner
regenerate thumbnails
remove featured images

I have tried playing with the CSS code:
.post-image {
display: none;
}

adding whatever I can find on the forums, but these stupid images persist!

I have tried to change the php but it’s beyond my knowledge and I keep breaking the site.

I can’t possibly make this site public. This is the only stupid theme (orfeo) I have managed to make work!! This forum is my last resort before going back to squarespace!

or can someone recommend a simple theme for beginners, that allows a custom header, custom colors, pages, and a blog post WITHOUT PLACEHOLDERS OR THUMBNAILS

The page I need help with: [log in to see the link]