diff --git a/src/Services/Attachments/AttachmentURLGenerator.php b/src/Services/Attachments/AttachmentURLGenerator.php
index c22cefe4..e505408f 100644
--- a/src/Services/Attachments/AttachmentURLGenerator.php
+++ b/src/Services/Attachments/AttachmentURLGenerator.php
@@ -112,12 +112,12 @@ class AttachmentURLGenerator
     /**
      * Returns a URL to a thumbnail of the attachment file.
      * For external files the original URL is returned.
-     * @return string|null The URL or null if the attachment file is not existing
+     * @return string|null The URL or null if the attachment file is not existing or is invalid
      */
     public function getThumbnailURL(Attachment $attachment, string $filter_name = 'thumbnail_sm'): ?string
     {
         if (!$attachment->isPicture()) {
-            throw new InvalidArgumentException('Thumbnail creation only works for picture attachments!');
+            return null;
         }
 
         if (!$attachment->hasInternal()){
diff --git a/src/Services/ImportExportSystem/EntityImporter.php b/src/Services/ImportExportSystem/EntityImporter.php
index cecab12d..11915cfb 100644
--- a/src/Services/ImportExportSystem/EntityImporter.php
+++ b/src/Services/ImportExportSystem/EntityImporter.php
@@ -57,6 +57,7 @@ class EntityImporter
     /**
      * Creates many entries at once, based on a (text) list of name.
      * The created entities are not persisted to database yet, so you have to do it yourself.
+     * It returns all entities in the hierachy chain (even if they are already persisted).
      *
      * @template T of AbstractNamedDBElement
      * @param string                           $lines      The list of names seperated by \n
@@ -132,32 +133,38 @@ class EntityImporter
             //We can only use the getNewEntityFromPath function, if the repository is a StructuralDBElementRepository
             if ($repo instanceof StructuralDBElementRepository) {
                 $entities = $repo->getNewEntityFromPath($new_path);
-                $entity = end($entities);
-                if ($entity === false) {
+                if ($entities === []) {
                     throw new InvalidArgumentException('getNewEntityFromPath returned an empty array!');
                 }
             } else { //Otherwise just create a new entity
                 $entity = new $class_name;
                 $entity->setName($name);
+                $entities = [$entity];
             }
 
 
             //Validate entity
-            $tmp = $this->validator->validate($entity);
-            //If no error occured, write entry to DB:
-            if (0 === count($tmp)) {
-                $valid_entities[] = $entity;
-            } else { //Otherwise log error
-                $errors[] = [
-                    'entity' => $entity,
-                    'violations' => $tmp,
-                ];
+            foreach ($entities as $entity) {
+                $tmp = $this->validator->validate($entity);
+                //If no error occured, write entry to DB:
+                if (0 === count($tmp)) {
+                    $valid_entities[] = $entity;
+                } else { //Otherwise log error
+                    $errors[] = [
+                        'entity' => $entity,
+                        'violations' => $tmp,
+                    ];
+                }
             }
 
-            $last_element = $entity;
+            $last_element = end($entities);
+            if ($last_element === false) {
+                $last_element = null;
+            }
         }
 
-        return $valid_entities;
+        //Only return objects once
+        return array_values(array_unique($valid_entities));
     }
 
     /**
diff --git a/tests/Services/ImportExportSystem/EntityImporterTest.php b/tests/Services/ImportExportSystem/EntityImporterTest.php
index 7c6f4d5d..fd5e8b9e 100644
--- a/tests/Services/ImportExportSystem/EntityImporterTest.php
+++ b/tests/Services/ImportExportSystem/EntityImporterTest.php
@@ -75,8 +75,8 @@ class EntityImporterTest extends WebTestCase
         $em = self::getContainer()->get(EntityManagerInterface::class);
         $parent = $em->find(AttachmentType::class, 1);
         $results = $this->service->massCreation($lines, AttachmentType::class, $parent, $errors);
-        $this->assertCount(3, $results);
-        $this->assertSame($parent, $results[0]->getParent());
+        $this->assertCount(4, $results);
+        $this->assertSame("Test 1", $results[1]->getName());
 
         //Test for addition of existing elements
         $errors = [];
@@ -113,6 +113,31 @@ EOT;
 
     }
 
+    public function testMassCreationArrow(): void
+    {
+        $input = <<<EOT
+        Test1 -> Test1.1
+        Test1 -> Test1.2
+        Test2 -> Test2.1
+        Test1
+            Test1.3
+        EOT;
+
+        $errors = [];
+        $results = $this->service->massCreation($input, AttachmentType::class, null, $errors);
+
+        //We have 6 elements, and 0 errors
+        $this->assertCount(0, $errors);
+        $this->assertCount(6, $results);
+
+        $this->assertEquals('Test1', $results[0]->getName());
+        $this->assertEquals('Test1.1', $results[1]->getName());
+        $this->assertEquals('Test1.2', $results[2]->getName());
+        $this->assertEquals('Test2', $results[3]->getName());
+        $this->assertEquals('Test2.1', $results[4]->getName());
+        $this->assertEquals('Test1.3', $results[5]->getName());
+    }
+
     public function testMassCreationNested(): void
     {
         $input = <<<EOT
@@ -132,15 +157,15 @@ EOT;
 
         //We have 7 elements, and 0 errors
         $this->assertCount(0, $errors);
-        $this->assertCount(7, $results);
+        $this->assertCount(8, $results);
 
-        $element1 = $results[0];
-        $element11 = $results[1];
-        $element111 = $results[2];
-        $element112 = $results[3];
-        $element12 = $results[4];
-        $element121 = $results[5];
-        $element2 = $results[6];
+        $element1 = $results[1];
+        $element11 = $results[2];
+        $element111 = $results[3];
+        $element112 = $results[4];
+        $element12 = $results[5];
+        $element121 = $results[6];
+        $element2 = $results[7];
 
         $this->assertSame('Test 1', $element1->getName());
         $this->assertSame('Test 1.1', $element11->getName());
diff --git a/translations/messages.en.xlf b/translations/messages.en.xlf
index 3f0387df..195366b4 100644
--- a/translations/messages.en.xlf
+++ b/translations/messages.en.xlf
@@ -7157,12 +7157,15 @@ Exampletown</target>
       </notes>
       <segment state="translated">
         <source>mass_creation.lines.placeholder</source>
-        <target>Element 1
+        <target><![CDATA[Element 1
    Element 1.1
       Element 1.1.1
    Element 1.2
 Element 2
-Element 3</target>
+Element 3
+
+Element 1 -> Element 1.1
+Element 1 -> Element 1.2]]></target>
       </segment>
     </unit>
     <unit id="TWSqPFi" name="entity.mass_creation.btn">