When you try to have Images collected from a webserver and you try get them loaded, they are loading for a very long time. Tabbing out and back into the game let those Images load instantly and without any problems. 

Also a suggestion would be to let the ServerOwner choose via a packet field or a field in the FormIcons JSON whether this Image should be cached client-sided or not, beceause if you have f.e. banners of factions that can easily change from time to time, it is annoying if they won't update beceause they are being cached.

Regards,
TobiasDev