No there isn't a way to hide them, unless your account has enough posts.
If you have 20 posts or more, the thumbnails at the top of the page get hidden.
If you have 2,000 posts or more, the ones at the bottom get hidden.
You maybe disappointed to learn there will be more thumbnail pics soon, but only if your account hasn't made a single post in previous 7 days.
In short, UKP will be jam-packed with links to UKE & PuntingWiki if you don't meet my minimum postcount criteria, because I want to take advantage of UKP's high levels of traffic.