don't show thumbanils

Good morning,
i live in italy and from a few day i try to use travelify theme, thank you so much for your theme and for the support.
I have a question about the visibility of the thumbnails immage, i try to insert a different immage for each page but i don’t see it.
Do you have a solution for my problem?
Thanks and sorry for my language!!!
Regards.

Paolo.

Hi Paolo,

I hope you are well today and thank you for your question.

It seems from your shared screenshot that you are trying to change your site header image which you can do from the header option as shown in the attached screenshot.

Best Regards,
Movin