diff --git a/05_typescript/uebungen/u04_without-any/src/main.ts b/05_typescript/uebungen/u04_without-any/src/main.ts
index 4b8567e..c2a5b6c 100644
--- a/05_typescript/uebungen/u04_without-any/src/main.ts
+++ b/05_typescript/uebungen/u04_without-any/src/main.ts
@@ -1,6 +1,6 @@
-const processData = (input: any): any => {
+const processData = (input: number): number => {
   return input * 2;
 };
 
-let result = processData('100');
+let result = processData(100);
 console.log(result);
diff --git a/05_typescript/unterricht/tag27/01_ts-fundamentals/assets/img/Understand-Typescript.jpg b/05_typescript/unterricht/tag27/01_ts-fundamentals/assets/img/Understand-Typescript.jpg
deleted file mode 100644
index c3a5d16..0000000
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diff --git a/05_typescript/unterricht/tag27/01_ts-fundamentals/assets/img/what-is-ts.webp b/05_typescript/unterricht/tag27/01_ts-fundamentals/assets/img/what-is-ts.webp
new file mode 100644
index 0000000..d329dbb
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diff --git a/05_typescript/unterricht/tag27/01_ts-fundamentals/index.html b/05_typescript/unterricht/tag27/01_ts-fundamentals/index.html
index 1b6c316..a87a717 100644
--- a/05_typescript/unterricht/tag27/01_ts-fundamentals/index.html
+++ b/05_typescript/unterricht/tag27/01_ts-fundamentals/index.html
@@ -17,7 +17,7 @@
           basiert und statische Typisierung zu JavaScript hinzufügt. Sprachkonstrukte von TypeScript, wie Klassen,
           Vererbung, Module und anonyme Funktionen, wurden auch in ECMAScript 6 übernommen.
         </p>
-        <img src="assets/img/Understand-Typescript.jpg" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
+        <img src="assets/img/what-is-ts.webp" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
       </div>
     </main>
   </body>
diff --git a/05_typescript/unterricht/tag28/01_ts-fundamentals/assets/img/Understand-Typescript.jpg b/05_typescript/unterricht/tag28/01_ts-fundamentals/assets/img/Understand-Typescript.jpg
deleted file mode 100644
index c3a5d16..0000000
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diff --git a/05_typescript/unterricht/tag28/01_ts-fundamentals/assets/img/what-is-ts.webp b/05_typescript/unterricht/tag28/01_ts-fundamentals/assets/img/what-is-ts.webp
new file mode 100644
index 0000000..d329dbb
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diff --git a/05_typescript/unterricht/tag28/01_ts-fundamentals/index.html b/05_typescript/unterricht/tag28/01_ts-fundamentals/index.html
index 0c9fa4e..ee17c90 100644
--- a/05_typescript/unterricht/tag28/01_ts-fundamentals/index.html
+++ b/05_typescript/unterricht/tag28/01_ts-fundamentals/index.html
@@ -24,7 +24,7 @@
           basiert und statische Typisierung zu JavaScript hinzufügt. Sprachkonstrukte von TypeScript, wie Klassen,
           Vererbung, Module und anonyme Funktionen, wurden auch in ECMAScript 6 übernommen.
         </p>
-        <img src="assets/img/Understand-Typescript.jpg" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
+        <img src="assets/img/what-is-ts.webp" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
       </div>
     </main>
   </body>
diff --git a/05_typescript/unterricht/tag29/01_ts-types/assets/img/Understand-Typescript.jpg b/05_typescript/unterricht/tag29/01_ts-types/assets/img/Understand-Typescript.jpg
deleted file mode 100644
index c3a5d16..0000000
Binary files a/05_typescript/unterricht/tag29/01_ts-types/assets/img/Understand-Typescript.jpg and /dev/null differ
diff --git a/05_typescript/unterricht/tag29/01_ts-types/assets/img/what-is-ts.webp b/05_typescript/unterricht/tag29/01_ts-types/assets/img/what-is-ts.webp
new file mode 100644
index 0000000..d329dbb
Binary files /dev/null and b/05_typescript/unterricht/tag29/01_ts-types/assets/img/what-is-ts.webp differ
diff --git a/05_typescript/unterricht/tag29/01_ts-types/index.html b/05_typescript/unterricht/tag29/01_ts-types/index.html
index bccbe85..b118e5f 100644
--- a/05_typescript/unterricht/tag29/01_ts-types/index.html
+++ b/05_typescript/unterricht/tag29/01_ts-types/index.html
@@ -23,7 +23,7 @@
           basiert und statische Typisierung zu JavaScript hinzufügt. Sprachkonstrukte von TypeScript, wie Klassen,
           Vererbung, Module und anonyme Funktionen, wurden auch in ECMAScript 6 übernommen.
         </p>
-        <img src="assets/img/Understand-Typescript.jpg" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
+        <img src="assets/img/what-is-ts.webp" alt="TypeScript Kreisdiagramm" class="img-thumbnail" />
       </div>
     </main>
   </body>