It’s crazy—Instagram has no provisions for posting images from a computer, only from a smart phone or similar.
Since my workflow always involve raw format with my regular cameras that’s a non-starter. As for my iPhone, I want to embed my copyright and so on, and tweak the image to my liking. So that means downloading and then deleting the images from the phone—so a phone for use with Instagram is useless to me.
I am sure there are other workarounds, like Lightroom plugins. But there are so many cases of having an existing image and being on a regular computer, that this approach is ideal, and very simple to do.
Update: reader Andrew H recommends Flume.
How to use Instagram from a computer
1. Enable the Develop menu in Safari as shown.
2. Fool Instagram.com into thinking your computer is an iOS device.
1. Create a new private window ().
2. Change the User Agent to iOS (
3. Go to Instagram.com and login.
4. Click the plus symbol at page bottom. A file open dialog will appear; choose the image and proceed.