This photo was taken with my previous medium format digital back – the Phase One IQ3 80, which provides a resolution of 10328 x 7760 pixels.
Clearly 80 megapixels is a little on the large size for Instagram, since the resolution limit for Instagram is 1,080 x 1,080 pixels. Given that I typically am posting a 4:3 aspect ratio image, that means Instagram is using around 1.5% of the captured resolution.
To demonstrate the resolution that is actually captured, I often post a “full frame” image, followed by one or more “macro” crops from that image at 100% resolution.
I can now embed in a blog post a full resolution, zoomable, panable image.
The image below is fully interactive, very simple to use, and enables you to fully explore the whole image at its full resolution. I recommend clicking the full screen icon, and then use the +/- icons to zoom in and out, and click-drag with your mouse (or use your finger on a touch interface) to pan around the image.