Cover Page Logo Displays at the Wrong Size

I've noticed a relatively new issue on my website where the logo on my cover page displays much smaller than it should (and slightly blurry).  When I refresh the page or revisit it soon after, the logo displays at the proper size.  I've tried re-uploading the PNG, playing with the logo size slider/number, switching to a GIF, and the issue persists.  This issue does not appear to happen in Chrome.  I'm viewing on an iMac.  Does anyone have any idea why this is happening or know a workaround?

here's the cover page: https://www.joshuakirsch.com

thanks!