Idea of Mailbox Opened Flag Up Icon
This is a picture of a mailbox. it's attached to a pole. it's front door is open wide and you can see inside it. it has a flag and it is sticking straight up.
This page shows the different variations of the Mailbox Opened Flag Up from an Icons8 icon pack. Feel free to resize and recolor the icon, and then download the icon in PNG format for free.