The new filters for Twitter are powered by Aviary, the same company that developed the image-editing software for other photo-sharing sites like Flickr. The move comes just two days after Instagram stopped allowing tweets to include Instagram photos, most likely in retaliation for Twitter's launch of the photo filters.
Pictures have become a very important focus of Twitter. The most widely circulated tweet of all time was a photo of a just re-elected President Barack Obama hugging the First Lady. Venture Capitalist Bijan Sabet, who helped put Aviary together with Twitter said, "From ordinary life to these special moments with artists, celebrities, or politicians, photos have always been this special thing for Twitter."
source: Reuters via SlashGear