iOS 13 Root.plist (for app settings) how to specify dark mode versions of icons

I have black volume icons for the slider in my app's settings. Now that iOS 13 supports dark mode, I can't really see those icons because they are black. How do I specify white versions of those icons? Are there 2 additional keys that specify that -OR- do I need to name the white versions of those icons something specific for the system to automatically use them?

<dict>

<key>Type</key>

<string>PSSliderSpecifier</string>

<key>Key</key>

<string>auto_audiolevel_minvalue</string>

<key>DefaultValue</key>

<real>50</real>

<key>MinimumValue</key>

<integer>50</integer>

<key>MaximumValue</key>

<integer>100</integer>

<key>MinimumValueImage</key>

<string>volumeAutoAdjustMin.png</string>

<key>MaximumValueImage</key>

<string>volumeAutoAdjustMax.png</string>

</dict>