It is recommended that a square (1:1) aspect ratio be used for top and bottom graphics that are included as part of the stitch.
Minimum suggested resolution: 10 x 10
Maximum suggested resolution: 1080 x 1080; depending on the streaming output resolution, a 720 x 720 graphic could also be used, but it may show pixelation if the Sphere is configured to stream at higher output resolutions. In this case, a 1080 x 1080 graphic should be used.
NOTE: the 10 x 10 resolution is not recommended unless you are using a single solid color in the graphic, as the image will be stretched to fill the top or bottom graphic.