Allows users to add and manage custom fields for the media post type
Yes! in addition to giving you the option to add custom fields, your custom fields will show up in all appropriate places. If you go to the media section to manage your media like you usually do, they will show up on the edit media form. The custom fields also show up when you are uploading an image to a post, and in all other expected locations.
Media items are stored in WordPress just like regular posts. This enables us to use native WordPress functions to store and retrieve your custom fields. Due to this, your data is stored in a very future-proof way, in the postmeta table of the WordPress database.
No, your data is not deleted when you uninstall the plugin. Data added to media items are considered to be linked to that media item, and not to the plugin, therefore there is no reason to remove it upon deactivation or uninstallation.
The plugin does two things. It enables you to create custom fields, and once created, enables you to add data to media items using those custom field. You can delete a custom field at any time, and choose weather you want to delete all the data you have entered using that custom field.
if you have created a custom field named "Photographer Name" and have added photographers to numerous photos, then subsequently delete the "Photographer Name" custom field, by default, your data will not be deleted with it. Each photo will still have the correct photographer assigned to it, however, you will not be able to modify this information until you recreate the "Photographer Name" custom field.
When deleting a custom field you can choose to delete all the data associated with that field. In this case, each photographer you added to an image will be removed and will no longer be accessible in any way, even if you recreate the same field.