add an image computed property to hostsymbol to return the Image so it safely returns an image from an sf symbol or an image from an ImageResource

ShhShell/Host/HostSymbol.swift

@@ -18,6 +18,14 @@ enum HostSymbol: Codable, Equatable, Hashable, CaseIterable {
 	case genericServer
 	case genericServerVertical
 	
+	var image: Image {
+		if isCustom {
+			return Image(self.sf)
+		} else {
+			return Image(systemName: self.sf)
+		}
+	}
+	
 	var sf: String {
 		switch self {
 		case .desktopcomputer:

ShhShell/Views/Keys/KeyDetailView.swift

@@ -51,7 +51,7 @@ struct KeyDetailView: View {
 							Button() {
 								hostsManager.set(keypair: keypair, onHost: host)
 							} label: {
-								Image(systemName: "plus")
+								host.symbol.image
 									.resizable().scaledToFit()
 									.foregroundStyle(.blue)
 									.frame(width: 20, height: 20)

ShhShell/Views/Misc/HostSymbolPreview.swift

@@ -13,15 +13,9 @@ struct HostSymbolPreview: View {
 	
     var body: some View {
 		ZStack(alignment: .center) {
-			if symbol.isCustom {
+			symbol.image
-				Image(symbol.sf)
 				.resizable().scaledToFit()
 				.symbolRenderingMode(.monochrome)
-			} else {
-				Image(systemName: symbol.sf)
-					.resizable().scaledToFit()
-					.symbolRenderingMode(.monochrome)
-			}
 			Text(label)
 				.font(.headline)
 				.offset(symbol.offset)