Does Imgur work for posting pictures?

Hi,
​I have a question about posting images from your desktop/files into your signature using Imgur. I've followed the instructions give but I can't see the pictures after pasting the URL in the 'Image' Box and clicking OK. All I see is a little box with an 'x' in it. Does anyone know how to fix this?

Please help.

I didn't find the right solution from the Internet.

References:
forum.schoolofdragons.com/content/does-imgur-work-posting-pictures
Medical Device Animation Examples

Thanks