It would be awesome if the pop-up media browser would limit the selectable assets based on the extension(s) selected in that field’s validation rules.
For instance, if I create a field called “Hero Image” that is a single asset type, with the “Accept only specified extensions” rule set to “Image”, I should only see images in the media browser when clicking on the “from gallery” button. At the moment we can select anything (videos, images, etc.) and will only see the validation error on the model page after the selection has happened and media browser has disappeared.