Twitter has just launched new tools that adjust the colour, size and style of photos users upload via its mobile app for iPhone and Android.The photo filters, developed in partnership with software maker Aviary, mimic the popular features that have defined Instagram, the booming photo app acquired by Facebook this year for $715 million.The move comes just days after Instagram unexpectedly said it would no longer allow Twitter to display Instagram photos.The reason, Instagram CEO Kevin Systrom said, was to drive visitors to Instagram's own website.Although Mr Systrom told Reuters last week he had no specific plans to disclose how he plans to monetise his service, analysts say Instagram would be a rich vein of advertising revenue for Facebook when, not if, the world's No 1 social network decides to tap it.The policy change better prepares Instagram for generating revenue from its service by driving traffic to its own properties where it might show advertisements, said Michael Gartenberg, an analyst at Gartner Inc.While the new filters affect a small slice of Twitter’s overall user experience, the move is symbolic in the escalating battle between Facebook and Twitter for dominance in the social media space. Mr Gartenberg said Facebook and Twitter are fighting for the attention of users, who have only so much time to devote to one service or another.Another bigger change is coming for Twitter users starting today: new profile pages. Twitter is updating everyone’s profile pages to make them look more like Facebook’s Timeline. Unless you want the “default grey image” on your page, you might want to upload a header image soon.The update has been available to a subset of users, but will roll out to all users today. The new profiles will include a large header image on the top of the page with a smaller profile picture in the centre of it. And just like the Timeline changes on Facebook, users don’t really have a choice about it — unless they want their profiles to look slightly off.