similar to my twitter card service Dewey [ http://deweybird.com ] being used by a few brands to share IG content to twitter [ https://twitter.com/budlight/sta... , https://twitter.com/HISTORY/stat... ].
Does it support video? Is this meant more as a fun tool for end users or are you looking to build a business on top of this? One decision I struggled with is the attribution of the twitter card. Reasoning behind attributing to your service (presumably to get exposure)?
Generally I think the approach is a little off. Platform context is important in social. The whole "auto cross post" nature is limiting.
I'd also encourage you to use deep linking, especially since Instagram makes their scheme public.
Idea Stash
SeenHunt for Chrome
Idea Stash
x-hed
SeenHunt for Chrome
GrowthHackers
SeenHunt for Chrome
GrowthHackers