Adding Alt Text | Google Docs, Facebook, Twitter, Instagram, Apple Pages, InDesign and Word

Although there is a lot work to be done to make technology as accessible as it can be, there are a lot of solutions out there that are simply not being used enough. Adding alternate text (alt text) to images for screen reader users is a great example of this. In this video I show you how you can add alt text in Google Docs, Facebook, Twitter, Instagram, Apple Pages, Adobe InDesign and Microsoft Word. Seven in roughly seven(ish) minutes

[jeromecollier]

When I create an alt text for a picture does that alt text stay with the photo wherever I post it? 
For Example, When creating an alt text on Google docs. Can I copy and post that same image onto instagram without create a alt text on the Instagram platform?