I'm developing a website where all a crowd of people will be uploading posts. To ensure the featured image on the post meets the requirements of other services the website will work with, I need to reject images users try to upload that are below a certain width or height. I would also need to reject images in vertical orientation.
I've looked through the source I was able to find for the media uploader, but I'm not sure where I should be adding in these customizations
