[Plugin: Ajax Event Calendar] Strange formmatting on calendar "arrow" graphics

Hi there, LOVE LOVE LOVE this plugin. Has come in very handy! Just wanted to know if there was a way to fix this weird issue with the arrow buttons–the image looks a little squished and not like an arrow. This is on Firefox. Thanks so much!

You can see what I mean here: http://i.imgur.com/9kFPZ.jpg

The page I’m referring to is: http://www.cabvi.org/calendar/