Thanks Chris for the nice global cloud with transparency and for your server.
What website do you know that it can be seen exactly as yours?

As you mentioned, the file only changes every three hours in your server.
What GMT time(s) does it change? It is important to know when, for noting the time element and so that I can know when to come back to see the newer image.

If for example it changes at 0900 GMT (it therefore changes also at 1200 GMT, 1500 GMT, 1800 GMT, 2100 GMT, 000 GMT, 0300 GMT and 0600 GMT), then when I look at it on 1000 GMT, at least I know that what I'm looking at occured one hour before. Then I can look at it again at the time I know it will change so I can compare the two.

D_a_n_t_e