hi, as this is a cover art it is required that the image is square, or of a 1:1 width height ratio. also the image that you uploaded is straight from the metronome english wikipedia page, and is licensed under CC-BY-SA 3.0 which requires that you credit the author of the image appropriately which you can find here
https://commons.wikimedia.org/wiki/File:Metronome_Nikko.jpg
it is important that you read the license terms of any image that you may want to use as part of your entry.
as an aside, i would also suggest that you turn this into more of a cover art image, maybe include a album title or "battleofthebits.com" somewhere or make it more stylised or unique in some way.