Hi!
I’m working on a site with Shapely theme (very cool theme) and i’ve the same issue
https://colorlibsupport.com/t/remove-featured-image-from-project-type-page/
but when i try the solution : Go to Appearance -> Customize -> Additional CSS and add this CSS Snippet in it,
.tax-jetpack-portfolio-type .entry-header img { display: none; }
It doesn’t work :’(
Maybe the code is different ?
Thanks to help me! 
Emma
Hello,
I hope you are doing well today.
Could you please give us a link to a project on your website so that I can see this issue?
This is a link to our demo and it only shows the image once so it does not reflect this issue that you are having:
Best Regards,
Support
Hello
Thanks for your quick answer!
Here is the link to the page : http://cosmicconcrete.com/portfolio/la-cour-des-aulnays
I don’t know how to remove the top picture (the black and white one)
Thanks again!
Emma
Hello,
Please try using this CSS code to remove the image then let me know if it worked:
.post-content .entry-header img {
display: none;
}
Best Regards,
Support
Hello!
Super!! It worked!
Thanks a lot! have a nice day.
Emma
Thank you too 
I will close this case now, Feel free to contact us again if you have other questions Thanks!