Per https://commons.wikimedia.org/wiki/Commons:Village_pump#We_have_a_winner_.28... :
From @wikicommons, RT by @wikimedia and @wikipedia:
The 25 millionth media file has just been uploaded to Wikimedia Commons, showing the Mevlid-i Halil Mosque in Turkey https://commons.wikimedia.org/wiki/File:Mevlid-i_Halil_Mosque_08.jpg#/media/...
FB/G+: The 25 millionth media file has just been uploaded to Wikimedia Commons! It shows the main courtyard of the Mevlid-i Halil Mosque, Şanlıurfa, Turkey. https://commons.wikimedia.org/wiki/File:Mevlid-i_Halil_Mosque_08.jpg
Feel free to suggest a different text. (Unfortunately the image isn't PD or CC0, so we can't upload it to Twitter directly.)