I am using the Enhanced Image Library plugin to automatically add a taxonomy to images uploaded to a custom post type. The plugin has a feature that will allow the post's categories to be automatically added to associated images when the image is uploaded.
However, if the post category is not assigned to the post before the images are added, then the images will not be categorized correctly. The easiest solution would be if there was a way to assign a default category directly after the "New Post" button was clicked, before the user has a chance to input any data into the post fields, and well before the save_post action.
All of the answers to this question that I found seem to reference the save_post or publish_post actions. Is there any action that can be utilized when "new post" is initially clicked?