Change feature image size and portfolio page image size

Hi there,

I’m a bit confused about your answer here because in another thread you do say that it possible:
https://colorlibsupport.com/t/change-feature-image-in-a-portfolio-page/

Or am I mixing up something?

Also I wanted to know how to not show the Image on a single portfolio item?

And another question, but a bit off topic: How can I change or remove the “Phone” “Adress” and “Email” Headings on the contact form?

Thank you very much in advance

Luca