Can't upload to my gallery: Firefox plugins.click_to_play security setting

This may help some (security conscious) people who are having problems:

I have the Firefox config (about:config) setting plugins.click_to_play set to true, but which defaults to false. However setting this to true prevents the upload in my gallery to work and it does not even show an icon where I can enable the plugin.

You can see no error, so its very unclear why the upload does not work...

So, If you plan to upload images, remember to (temporarily) set it back to false...