vanishing logo

I have a header on my blog, with a logo on the left – a drawing of a monkey putting on an Ankylosaur tail. In the past it’s always shown up OK. It still shows up OK when I look at it on my smartphone, but it’s disappeared from my PC screen, to be replaced by a placeholder and the alt text that goes with the image. This is the same in all the different browsers I’ve tried.

I’m using the latest version of the Astra theme. The logo looks perfectly OK when I go into the controls for setting up the header and, as I say, it’s there and correct if I access the blog via my smartphone.

I recently upgraded to a high-resolution monitor – but I can’t see why that would make a difference. I’ve linked to the top page of my blog, so I’d appreciate it if somebody else could look, on their PC, and tell me whether or not they can see a drawing of a monkey pulling a club on over its tail. That at least will tell me whether the problem is with the blog or with my PC setup.

The page I need help with: [log in to see the link]