Hi, @yfchild.
A new option with this plugin would be to have the possibility to read the image from a folder (wp-content/upload/myfolder) that contains multiple images
Normally images in the upload image are public. So they have an URL and you could use it into the FIFU field. But FIFU won’t choose the image, of course.
You could use the function fifu_dev_set_image($post_id, $image_url)
with a code to read the folder and randomize the image chosen. Done.
For now it can’t be native because it’s a very uncommon thing. Never someone requested that before. So I only can implement the most common requests.
them and puts it as featured image and in the media library
There is already a feature for that. Take a look at FIFU Settings > Featured image > Save in the media library.