Http Error When trying To Upload Images

First I would recommend deactivating all plugins to see if that resolves the issue. If it does, then reactivate the plugins one by one to try and target the culprit. If that doesn’t work, this article may help provide further insight to your problem. Hope this helps get you started.

http://www.wpbeginner.com/wp-tutorials/how-to-fix-image-upload-issue-in-wordpress/