default color for the designs

For the text there is a default color setting, is there also a default color setting for the imported designs?

i found this explanation, 

"Disable color changes

To fix the color of an element to a specific value and to not allow the customer to change it, use an image in the correct color or use the current color option, and delete all other color choices."

and it works for designs in every color except white, then they are not vissible in the selection menu 

is there a workarround for this? am i missing something in the settings?

Is it possible to use for example black png files en set for each product a default color that design