The Server Panel Icons have Vanished

Within the editor all the builti-in icons have vanished, making it impossible to use the ingame editor.

Is there an image hosting problem ? 
I'm using the default stuff.

Very stupidly I delted parts of my config by trying to use the editor in game. 
 

Are you getting any errors from ImageLibrary?

4 hours ago, MeventSupport said:

Are you getting any errors from ImageLibrary?

On further investigation, I noticed ImageLibrary is getting a "failed to call hook error" - only on server startup. 
Other than this I have never noticed any imagelibrary problems or console errors during  the last few days, when reloading ServerPanel or any related plugins that are using ImageLibrary on our server.
 

[Error] Failed to call hook 'AddImage' on plugin 'ImageLibrary v2.0.62' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.ImageLibrary.AddImage (System.String url, System.String imageName, System.UInt64 imageId, System.Action callback) [0x00044] in <21179633d4114e16ab24a4a44d8b9cc3>:0 
  at Oxide.Plugins.ImageLibrary.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00781] in <21179633d4114e16ab24a4a44d8b9cc3>:0 
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <42f9bedc659b4f4786eb778d3cd58968>:0 
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000de] in <8cb2d664f1574f2b96d53f1c1869d96a>:0 
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <8cb2d664f1574f2b96d53f1c1869d96a>:0