If you run your game and your the player that you selected is not showing up, check the console and see if you have an error that looks like this one:
What the error is saying is that it was unable to find the picture in the file path I gave. This error is usually caused by a spelling error in either the name of the PNG or somewhere in the file path. The file path is telling the code which folders it need to go through in order to find the PNG, so to check on how you spelled everything find your line of code where you state what file you wish to use, and expand the correct folders.
So you can see each of the 2 folders and then the file name (each circled in red) listed inside of the file explorer from Atom. In the line of code the path file follows the same order. We first go to spot 1 which is assets. Double check your spelling there. If the spelling in your code matches the spelling of the folder in the explorer move to the second spot. You can see from my example that I left off the s at the end of players, which is why I was receiving the error.
Other things to look for are that your code has the name of the png followed by .png and that the entire file path is surrounded by ' '. If you have checked all of that, saved your file and refreshed mongoose, but are still having an error then check out this article.