The picture displays the text "If everyone, who cares about Democracy, joined Mastodon and left X/Twitter, Democracy would be in a much better shape. - Sign the petition www.openpetition.de/Unis4Mastodon" Moreover, a laughing Mastodon mascott is shown, looking rather content with this message.
https://bewegung.social/system/media_attachments/files/112/151/082/474/567/908/original/795a6cee35482d43.png