Formatter not showing

I have updated for this Warning: Undefined array key "#view_mode" in paragraphs_responsive_background_image_formatter_preprocess_paragraph() in above attached patch

Thanks for the patch, I confirm that it resolves the warning.

In other news I have realised why I wasn't seeing 'Paragraphs Responsive Background Image' as a formatter - I misunderstood the instruction (on the module's project page): 'Create or modify the media image display settings and choose Paragraphs Responsive Background Image as the formatter'. I thought this was referring to the media image field referenced in the preceding step and that the reference to 'modify the media image display settings' was to to the formatter's options (the gear button).

I now realise you were actually instructing the reader to create a new Media Type (of type image) and then in the 'Manage display' of that new media type to set the formatter there. You may want to consider enhancing those instructions.

In any case, thanks for the patch!