Twitter has unveiled its own photo filters which are live on the latest versions of the iOS and Android apps, according to a blog post. The micro-blogging site is working with Aviary to power the filters and effects, which was selected as Flickr's online photo editor back in April. Twitter is offering eight filters: vignette, black and white, warm, cool, vintage, cinematic, happy, and gritty. To use one, upload a photo to Twitter as you normally would by clicking...