Customizing badge color

[sarah....@gmail.com]

Hi,

I'm wondering if I can change the background color of the badges I create? I tried uploading a custom images but it appears quite small even if I change the size to make it bigger. Could you please let me know if I can change the color of the badge to differentiate tracks or the expected image size to upload so it looks similar in size to the default image?

Thanks,

Sarah