When you share a photo on Instagram, regardless of whether you're using Instagram for iPhone or Android, we make sure to upload it at the best quality resolution possible (up to a width of 1080 pixels).

When you share a photo that has a width between 320 and 1080 pixels, we keep that photo at its original resolution as long as the photo's aspect ratio is between 1.91:1 and 4:5 (a height between 566 and 1350 pixels with a width of 1080 pixels). If the aspect ratio of your photo isn't supported, it will be cropped to fit a supported ratio. If you share a photo at a lower resolution, we enlarge it to a width of 320 pixels. If you share a photo at a higher resolution, we size it down to a width of 1080 pixels.

If you want to make sure that your photo is shared with a width of 1080 pixels: