Replace placeholder puppies with final ones

src/index.htm

@@ -23,7 +23,7 @@
     <div class="max-w-4xl mx-auto">
       <div class="flex flex-wrap mx-auto">
         <div class="sm:w-full md:w-1/2 lg:w-1/3">
-        <img src="img/aspiring-writer.png" />
+        <img src="img/professor.png" />
         </div>
         <div class="sm:w-full md:w-1/2 lg:w-2/3 p-10">
           <a name="backed-by-experience">
@@ -35,7 +35,7 @@
       </div>
       <div class="flex flex-wrap sm:flex-row md:flex-row-reverse mx-auto bg-blue-200">
         <div class="sm:w-full md:w-1/2 lg:w-1/3">
-          <img src="img/researcher.png" />
+          <img src="img/naturalist.png" />
         </div>
         <div class="sm:w-full md:w-1/2 lg:w-2/3 p-10">
           <a name="stories-before-statistics">
@@ -47,7 +47,7 @@
       </div>
       <div class="flex flex-wrap mx-auto">
         <div class="sm:w-full md:w-1/2 lg:w-1/3">
-        <img src="img/established-writer.png" />
+        <img src="img/teacher.png" />
         </div>
         <div class="sm:w-full md:w-1/2 lg:w-2/3 p-10">
           <a name="learning-through-teaching">