How do I save high-resolution versions of my filtered photos?
High-resolution versions of your Instagram photos are saved to your phone after you upload the photo to Instagram, and you're the only one who has access to them. You have to turn on the Save Original Photos setting in your Account Settings to make sure filtered photos save to your phone.
We'll always save images in the highest resolution size possible. The maximum resolution on both Android and iOS is 2048x2048, but your phone’s resolution capabilities may be lower than that.
Image resolution capabilities are different for each phone.
Photo resolution taken with the Instagram camera (not the iPhone Camera app) and saved to your phone are:
2048x2048 on the iPhone 4s and up
1936x1936 on the iPhone 4
1536x1536 on the iPhone 3GS
Keep in mind that photos imported from iOS (not taken with the Instagram camera) and then uploaded to Instagram will save at a much lower resolution (612x612). Apple has recently updated their API to allow high resolution importing to apps, but we don't know when this feature will be available.