Changing the size of the portifolio image thumbnails in Welfare NGO theme

wordpress

#1

I would like to change the size of the portifolio image thumbnails on my website (slowfooduganda.org) to a size similar to the one on this website: http://www.fondazioneslowfood.com/en/. I have tried everything including changing the size of the featured images on the projects but nothing seems to work. Please help.

Also, the default background color of the main menu items as well as the font color for the menu items on my Welfare NGO theme changed unexpectedly. Which color scheme setting do I need to change to get it back to it its default?

Thank you.