The dimensions expected for the image are also dependent on the ContentType meta data value being specified:
http://sdkdocs.roku.com/display/RokuSDK ... oardScreen•Orientation for artwork is based on ContentType setting and may be portrait or landscape.
•The audio springboard is capable of adding a progress bar.
•If the ContentType is audio, the album art dimensions are:
SD: 124 x 112
HD: 188 x 188
•If the ContentType is episode, the album art dimensions are:
SD: 180 x 122
HD: 264 x 198
•If the ContentType is any other value, the album art dimensions are:
SD: 112 x 142
HD: 148 x 212
Can you check what value you are setting?