Thank you for your question regarding the background of military symbols
generated in the PNG format using www.symbol.army.
I assume
you are referring to the background of the symbols:
If yes, this can be set in the Options Menu of the web application.
1. Open the
Options Menu
2. Deactivate
the Symbol Filled option in the 1-Point Symbol section
Hint: To set the symbol to black and white display deactivate the Colored option in the Options Menu of the web application: