Intermittent issues with page loading speed

There is an issue with communities page loading speed from different local offices.  Sometimes portal is almost unusable as it takes forever to load any page in communities.bentley.com while other sites work correctly.It appears that the main bottleneck is that some images are very slow to load using SSL.


For example when experiencing slowdowns this image(HTTPS) doesn't load at all:

While this image loads instantly(HTTP):