diff --git a/CHDataManagement/Model/ImageResource.swift b/CHDataManagement/Model/ImageResource.swift
index 66ffbc3..31285e4 100644
--- a/CHDataManagement/Model/ImageResource.swift
+++ b/CHDataManagement/Model/ImageResource.swift
@@ -35,8 +35,8 @@ final class ImageResource: ObservableObject {
         self.germanDescription = de
     }
 
-    init(resourceName: String) {
-        self.type = ImageType(fileExtension: resourceName.fileExtension!)!
+    init(resourceName: String, type: ImageType) {
+        self.type = type
         self.id = resourceName
         self.source = .resource(resourceName)
         self.englishDescription = "A test image included in the bundle"
diff --git a/CHDataManagement/Preview Content/MockImage.swift b/CHDataManagement/Preview Content/MockImage.swift
index 2c243a8..a4af9b1 100644
--- a/CHDataManagement/Preview Content/MockImage.swift	
+++ b/CHDataManagement/Preview Content/MockImage.swift	
@@ -7,7 +7,7 @@ struct MockImage {
 
     static var images: [ImageResource] {
         ["image1", "image2", "image3", "image4"]
-            .map(ImageResource.init)
+            .map { ImageResource(resourceName: $0, type: .jpg) }
     }
 }
 
diff --git a/CHDataManagement/Preview Content/Tag+Mock.swift b/CHDataManagement/Preview Content/Tag+Mock.swift
index 756687c..a57c2c0 100644
--- a/CHDataManagement/Preview Content/Tag+Mock.swift	
+++ b/CHDataManagement/Preview Content/Tag+Mock.swift	
@@ -34,7 +34,7 @@ extension LocalizedTag {
         name: "Electronics",
         subtitle: "Projects with electronics",
         description: "Some description of the tag",
-        thumbnail: ImageResource(resourceName: "image1"),
+        thumbnail: ImageResource(resourceName: "image1", type: .jpg),
         originalUrl: "projects/electronics")
 
     static let german = LocalizedTag(
@@ -42,6 +42,6 @@ extension LocalizedTag {
         name: "Elektronik",
         subtitle: "Projekte mit Elektronik",
         description: "Eine Beschreibung des Tags",
-        thumbnail: ImageResource(resourceName: "image2"),
+        thumbnail: ImageResource(resourceName: "image2", type: .jpg),
         originalUrl: "projects/electronics")
 }
diff --git a/CHDataManagement/Views/Images/ImagesContentView.swift b/CHDataManagement/Views/Images/ImagesContentView.swift
index da4f769..997512d 100644
--- a/CHDataManagement/Views/Images/ImagesContentView.swift
+++ b/CHDataManagement/Views/Images/ImagesContentView.swift
@@ -13,5 +13,5 @@ struct ImagesContentView: View {
 }
 
 #Preview {
-    ImagesContentView(image: .init(resourceName: "image1"))
+    ImagesContentView(image: .init(resourceName: "image1", type: .jpg))
 }