The owner or an admin can open Room Settings → Background to choose an image or upload one, then adjust how it looks.
Background type
Fixed / Full Width keeps the background in place as a backdrop. Scrolling lets the background move as you travel around the room.
Layout
Centered shows one image. Tiled repeats it across the space, which works well for patterns or textures.
Size and color
Use Size to adjust how large the background appears. Color chooses the color behind the image and around areas it does not cover.
Try centered for a single illustration, or tiled for a repeating wallpaper. Start with a smaller image if a large upload is slow to load.