diff --git a/Package.swift b/Package.swift
new file mode 100644
index 0000000..a2507f5
--- /dev/null
+++ b/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
+]
diff --git a/XCAssetPacker/ImageProperties.swift b/XCAssetPacker/ImageProperties.swift
index fbbc452..d5357af 100644
--- a/XCAssetPacker/ImageProperties.swift
+++ b/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
             }
         }
     }
diff --git a/XCAssetPacker/main.swift b/XCAssetPacker/main.swift
deleted file mode 100644
index 390bdfb..0000000
--- a/XCAssetPacker/main.swift
+++ /dev/null
@@ -1,167 +0,0 @@
-//
-//  main.swift
-//  XCAssetPacker
-//
-//  Created by Harry Jordan on 23/11/2016.
-//  Copyright © 2016 Inquisitive Software. All rights reserved.
-//	
-//  Licensed under the Apache License, Version 2.0 (the "License");
-//  you may not use this file except in compliance with the License.
-//  You may obtain a copy of the License at
-//  
-//  http://www.apache.org/licenses/LICENSE-2.0
-//  
-//  Unless required by applicable law or agreed to in writing, software
-//  distributed under the License is distributed on an "AS IS" BASIS,
-//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//  See the License for the specific language governing permissions and
-//  limitations under the License.
-// 
-
-import Foundation
-
-import Foundation
-import Cocoa
-
-
-let versionNumber = "1.2"
-
-// Setup command line options
-let inputPathOption = StringOption(shortFlag: "i", longFlag: "input", helpMessage: "Path to the input folder.")
-let configurationOption = StringOption(shortFlag: "c", longFlag: "config", required: false, helpMessage: "The location of a json configuration file.\n      If none is specified then uses sensible defaults.")
-let outputPathOption = StringOption(shortFlag: "o", longFlag: "output", helpMessage: "Path to the output file or folder.\n      If a folder is given then an Assets.xcassets package will be created inside it.")
-let swiftDestinationOption = StringOption(longFlag: "swift", helpMessage: "Path to the output swift file or folder.\n      If a folder is given then an Images.swift file will be created inside it.")
-let overwriteOption = BoolOption(shortFlag: "f", longFlag: "force", helpMessage: "Overwrite any existing .xcassets package or Swift file.")
-
-// Target
-let swiftTargetMacOption = BoolOption(longFlag: "mac", helpMessage: "Set the target for generated Swift to use Cocoa.")
-let swiftTargetiOSOption = BoolOption(longFlag: "iOS", helpMessage: "Set the target for generated Swift to use UIKit.")
-let swiftTargetWatchOption = BoolOption(longFlag: "watch", helpMessage: "Set the target for generated Swift to use WatchKit.")
-
-let versionOption = BoolOption(shortFlag: "v", longFlag: "version", helpMessage: "Prints the version number.")
-let helpOption = BoolOption(shortFlag: "h", longFlag: "help", helpMessage: "Prints a help message.")
-
-
-let cli = CommandLine()
-cli.addOptions(inputPathOption, configurationOption, outputPathOption, swiftDestinationOption, swiftTargetMacOption, swiftTargetiOSOption, swiftTargetWatchOption, overwriteOption, versionOption, helpOption)
-
-
-do {
-    try cli.parse()
-} catch {
-    cli.printUsage(error)
-    exit(EX_USAGE)
-}
-
-
-if helpOption.value {
-    cli.printUsage()
-    exit(EX_USAGE)
-}
-
-if versionOption.value {
-    print("XCAssetPacker version \(versionNumber)")
-    exit(EX_USAGE)
-}
-
-
-
-guard inputPathOption.wasSet && outputPathOption.wasSet else {
-    print("Missing required options: [-i or --input, and -o or --output]\n")
-    cli.printUsage()
-    exit(EX_USAGE)
-}
-
-
-let inputPath = inputPathOption.value
-let outputPath = outputPathOption.value
-let shouldOverwrite: Bool = overwriteOption.value
-
-
-// Determine input URL
-let fileManager = FileManager()
-let sourceDirectoryURL: URL
-
-if let input = inputPath {
-    sourceDirectoryURL = URL(fileURLWithPath: input)
-} else {
-    sourceDirectoryURL = URL(fileURLWithPath: fileManager.currentDirectoryPath)
-}
-
-
-// Determine output URL
-var destinationDirectoryURL: URL
-
-if let output = outputPath {
-    destinationDirectoryURL = URL(fileURLWithPath: output).absoluteURL
-} else {
-    destinationDirectoryURL = URL(fileURLWithPath: fileManager.currentDirectoryPath)
-}
-
-
-// Validate swift url
-var swiftDestinationURL: URL?
-
-if let swiftDestinationPath = swiftDestinationOption.value {
-    swiftDestinationURL = URL(fileURLWithPath: swiftDestinationPath).absoluteURL
-} else if swiftDestinationOption.wasSet {
-    swiftDestinationURL = URL(fileURLWithPath: fileManager.currentDirectoryPath)
-}
-
-let swiftTarget: SwiftTarget
-
-if swiftTargetMacOption.wasSet {
-    swiftTarget = .cocoa
-} else if swiftTargetWatchOption.wasSet {
-    swiftTarget = .watch
-} else {
-    swiftTarget = .iOS
-}
-
-
-// Load a configuration .json
-var configuration: [String: Any] = [:]
-
-if let configurationFilePath = configurationOption.value {
-    let configurationFileURL = URL(fileURLWithPath: configurationFilePath).absoluteURL
-    
-    if let data = try? Data(contentsOf: configurationFileURL),
-        let json = try? JSONSerialization.jsonObject(with: data, options: []),
-        let configurationJSON = json as? [String: Any] {
-        configuration = configurationJSON
-    }
-}
-
-
-do {
-    // Build a catalog of available images
-    let assetCatalog = try AssetCatalogGenerator(from: sourceDirectoryURL, to: destinationDirectoryURL, swift: swiftDestinationURL, target: swiftTarget, overwrite: shouldOverwrite, configuration: configuration)
-    
-    // Generate the output packages and files
-    let log = try assetCatalog.applyChanges()
-    
-    // Print
-    let suffix = assetCatalog.destinationURL.pathComponents.suffix(4)
-    let lastPathComponents = suffix.reduce("") { (combined, pathComponent) -> String in
-        return combined + "/" + pathComponent
-    }
-    
-    print("Created assets package \(lastPathComponents) containing \(log.numberOfImages) images")
-    exit(EXIT_SUCCESS)
-} catch let error as AssetCatalogError {
-    switch error {
-    case .ioError(let description):
-        print(description)
-        exit(EX_IOERR)
-    }
-} catch let error as SwiftGenerationError {
-    switch error {
-    case .duplicateProperty(let name, originalFileName: let originalFileName):
-        print("Conflicting property '\(name)' for \(originalFileName)")
-        print("Images need to have distinct llama case representations")
-        exit(EX_IOERR)
-    }
-} catch let error {
-    print("Unexpected error: \(String(describing: error))")
-    exit(EX_IOERR)
-}