Thanks Andy, although still having major issues with this 
The dimensions in the documentation (which is now updated as per your last post) still appear to not work and cause the images to be ‘cut-off’.
I am also still suffering from really bad quality due to your compression rates. How is this possible on an image that is barely 11kb, in PNG format and within the image dimension/resolution specified?
You can see an example at https://twitter.com/simon123test, notice the awful pixelation around the text?
I look forward to your response and a fix for this.