Hi,
While the cause of this issue is nothing that Pixel tail can resolve I hope that you will be able to come up with a solution that avoids it reoccurring in the future.
The problem:
Tower unite uses web addresses (URLS) to store textures for primitives, such as canvases etc, when loading into condos. This includes all custom maps.
However Imgur has now blocked UK users from accessing their site for reasons that are too long and complex to go into here. As a result all textures stored there now display ‘Content not available in your region.’ and not the texture if you are in the UK.
While you folks cannot do anything about this it raises an issue with the longevity of Tower Unite and in particular custom maps. Any external image store site could just shut down at any time, resulting in custom maps breaking. It also means I am going to have to go through my maps and try and fix this (ugh 
).
However Steam stores the textures as part of the map blob and you have to upload them as part of the workshop submission. As a result they are on Valve’s servers. Further (unless something has changed recently) all the map and the textures are downloaded from the hosts PC when a map is played.
As a result there is no need, other than I suspect a historical one, for the textures to be stored on an external site, and one that could just vanish at any time.
So can the condo editor be updated so that it has the option to pull textures from the map blob rather than an external site?
I’ve marked this as a bug as the Imgur lock out is going to affect all custom maps for UK users and indeed any other users in the event of imgur (or any image hosting site they use) withdrawing from their territory.
Quick edit having investigated further: This is actually harder for me to fix than I expected as the alternatives I have tried do not preserve png transparency, thus signs are black squares rather than black writing over the background texture (wood or whatever).