changed default scale to nil, to handle vector (pdf) files

Package.swift

@@ -0,0 +1,16 @@
+// swift-tools-version:4.0
+import PackageDescription
+
+let pkg = Package(name: "XCAssetPacker")
+pkg.products = [
+    .library(name: "XCAssetPacker", targets: ["XCAssetPacker"]),
+]
+pkg.dependencies = [
+]
+
+let pmk: Target = .target(name: "XCAssetPacker", dependencies: [])
+pmk.path = "XCAssetPacker"
+
+pkg.targets = [
+    pmk
+]

XCAssetPacker/ImageProperties.swift

@@ -106,8 +106,8 @@ struct ImageProperties {
                 // Look for a base scale in the configuration file
                 return scaleString
             } else {
-                // Otherwise default to 1x
-                return "1x"
+                // Otherwise return nil, for matching vector files without a scale
+                return nil
             }
         }
     }