Like it or loath it, Instagram is here to stay - at least for a while.  If you use Lightroom there is a plugin you can obtain to directly load the images you choose from lightroom to  Instagram.

Go to this site and download the plugin.

Once it is unzipped you will see a simple Read Me file to get the plugin installed into Lightroom.

Tips:

1. Some people don't use "Publish Services" much in Lightroom.  To see this module, in Library view, right click and enable it in the drop down.

2. The plugin will make its own collection that you need to put your images in called "Instagram photos".  This won't reside in the normal Collections space, but in the Publish Services area.

Last note, you  get a option to donate to the company/person that made this plug in.  Do so if you use it and find it useful.