Pin Thumbnail is Goofy

I just installed this plugin on a new site and it’s displaying the pins differently than it usually does (I have it on several sites). In the sidebar widget, it’s showing the top left corner of a smaller version of each pin (which often is just dead space), rather than a small thumbnail of nearly the entire pin. I can’t for life of me figure out why this is happening. I’d be very grateful if you could help me fix this!

https://wordpress.org/plugins/pinterest-rss-widget/