[BUGFIX] Set PropertyMappingConfiguration for image uploads

This change configures the ``PropertyMapper`` to allow mapping the
``resource`` to the ``image`` object.

Change-Id: I9672f0b90d2ec879af7e10806bc8413b8a704949
Releases: master, 2.0

Classes/TYPO3/Form/FormElements/ImageUpload.php

@@ -12,6 +12,9 @@
  *                                                                        */
 
 use TYPO3\Flow\Annotations as Flow;
+use TYPO3\Flow\Property\PropertyMappingConfiguration;
+use TYPO3\Flow\Property\TypeConverter\PersistentObjectConverter;
+use TYPO3\Media\TypeConverter\AssetInterfaceConverter;
 
 /**
  * An image upload form element
@@ -22,6 +25,13 @@ class ImageUpload extends \TYPO3\Form\Core\Model\AbstractFormElement {
 	 * @return void
 	 */
 	public function initializeFormElement() {
+		/** @var PropertyMappingConfiguration $propertyMappingConfiguration */
+		$propertyMappingConfiguration = $this->getRootForm()->getProcessingRule($this->getIdentifier())->getPropertyMappingConfiguration();
+
+		$propertyMappingConfiguration->setTypeConverterOption(PersistentObjectConverter::class, PersistentObjectConverter::CONFIGURATION_CREATION_ALLOWED, TRUE);
+		$propertyMappingConfiguration->setTypeConverterOption(AssetInterfaceConverter::class, AssetInterfaceConverter::CONFIGURATION_ONE_PER_RESOURCE, TRUE);
+		$propertyMappingConfiguration->allowProperties('resource');
+
 		$this->setDataType('TYPO3\Media\Domain\Model\Image');
 		$imageTypeValidator = new \TYPO3\Media\Validator\ImageTypeValidator(array('allowedTypes' => $this->properties['allowedTypes']));
 		$this->addValidator($imageTypeValidator);