After pasting the youtube link into the youtube uploader the resulting thumbnail image is much larger than the editor dimensions.

Can the thumbnail be automatically resized to fit within the editor dimensions OR The editor resize to allow the whole thumbnail to be seen?  

Hi earbash,

You can set property  ResizeMode="AutoAdjust", then editor will auto adjust the height.

Another way is use the external css to adjust the youtube thumbnail size in edit mode.

1. set  editor.EditorWysiwygModeCss="example.css"

2. add the code below into the example.css

Regards,

Ken 

Brilliant, thanks Ken

A combination of both options worked a treat!