Featured image / timthumb settings

Hello everyone ??
I’m using theme Catalyst on https://www.inquest.pl
In featured pages, we have an option to choose an featured image for it, which is before the actual text on the page (and also in that fancy sliding images on the main page). If you enter for example ‘e-szkolenia’ you can see that image are cropped, even when I upload it I check option “full size”.
Well, if you look into source you can find that timthumb cropped it.

Where I can find options to set width/height of the featured images INSIDE featured pages?

I tried to delete the featured image, and simply put image inside of featured page – but then I don’t have any image in that fancy sliding gallery on the main page ??

cheers!