Thanks Kelly, that worked nicely. I inserted this snippet as a test. Found the Custom (Expression) menu option hidden at the bottom of the Choose attribute to show list. The next step is to find or create some high quality tropical cyclone symbols with background transparency.
Function showImg(value){
if (value == '1'){
return 'TC1a.png'
}
if (value == '0'){
return 'TC1b.png'
}
}
showImg($feature.category)