A page showing three grids that show the conversion from pixels to hex numbers. It says: A 1bpp tile is a set of 8 bytes that encode the state of its 8x8 pixels. Each pixel can be on (1) or off(0). There is a drawing of a uxn balloon dropping pixels onto a little construction site.
https://assets.merveilles.town/media_attachments/files/107/808/836/050/297/199/original/8e941f986c1293cc.png