Confirming yesterday's reports, Twitter has indeed launched an update with image filters. Available now for Android and landing soon on iOS, the updated app packs eight different image filters, as well as extremely basic editing functionality.
The app's toolset isn't nearly as diverse as many more mature photo-editing apps. All it can do to edit is crop and auto enhance, and all the filters are extremely simple. What's interesting is that this whole editing engine is powered by the extremely popular Aviary SDK, which spread to mobile earlier this year, and is the same editor that Flickr currently uses.