If the custom icons you uploaded are appearing too big, make sure to resize them before uploading. We suggest a size of around 100 by 100 pixels. The icons will display at half size (so that the resolution is great).
Uploading an icon (PNG format best) of around 100 by 100 pixels will then be displayed at around 50 by 50 pixels, which is optimal. Of course, you can increase or decrease sizing however you'd like to achieve the desired design/appearance.