diff --git a/CHANGELOG_en-GB.md b/CHANGELOG_en-GB.md
index 35a49af..94994d3 100644
--- a/CHANGELOG_en-GB.md
+++ b/CHANGELOG_en-GB.md
@@ -1,3 +1,6 @@
+# 3.0.2
+* Add auto update of thumbnails after changing thumbnailSizes: no more need to run "media:generate-thumbnails"
+
 # 3.0.1
 * Add configuration to set maximum size for original image
 * Add configuration to specify file extension which can be processed
diff --git a/README.md b/README.md
index f39e533..bd0f714 100644
--- a/README.md
+++ b/README.md
@@ -53,7 +53,7 @@ You may want to delete folder `thumbnails` within folder `public`
 
 ## Adding more thumbnail sizes:
 - Save new size in the folder of the media management
-- then run the command `bin/console media:generate-thumbnails` on the console to update the thumbnails for all images in the database
+- (up to and including plugin version 3.0.1) then run the command `bin/console media:generate-thumbnails` on the console to update the thumbnails for all images in the database
 - Clear shop cache
 
 ## Find Patterns
diff --git a/composer.json b/composer.json
index fd59635..aeff444 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
         "thumbnail"
     ],
     "description": "This plugins allows you to use variable thumbnails, without having them on storage.",
-    "version": "3.0.1",
+    "version": "3.0.2",
     "type": "shopware-platform-plugin",
     "license": "mit",
     "authors": [
diff --git a/phpstan.neon b/phpstan.neon
index 90367d2..a9c7019 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -2,5 +2,17 @@ parameters:
     level: 9
     paths:
         - src
-    excludePaths:
-        - src/DependencyInjection/ThumbnailService.php
+    ignoreErrors:
+        -
+            message: "#^Call to an undefined method Shopware\\\\Core\\\\Content\\\\Media\\\\Message\\\\GenerateThumbnailsMessage\\:\\:setContext\\(\\)\\.$#"
+            count: 1
+            path: src/DependencyInjection/FileSaver.php
+
+        -
+            message: "#^Parameter \\#1 \\$objectOrClass of class ReflectionClass constructor expects class\\-string\\<T of object\\>\\|T of object, string given\\.$#"
+            count: 1
+            path: src/DependencyInjection/GeneratorCompilerPass.php
+
+        -
+            message: "#^Method Frosh\\\\ThumbnailProcessor\\\\DependencyInjection\\\\ThumbnailService\\:\\:(.*)\\(\\) is unused\\.$#"
+            path: src/DependencyInjection/ThumbnailService.php
diff --git a/src/DependencyInjection/GeneratorCompilerPass.php b/src/DependencyInjection/GeneratorCompilerPass.php
index cb904a6..608ee5d 100644
--- a/src/DependencyInjection/GeneratorCompilerPass.php
+++ b/src/DependencyInjection/GeneratorCompilerPass.php
@@ -92,7 +92,11 @@ private function handleThumbnailService(NodeFinder $nodeFinder, array $ast): voi
 
         // we don't need to generate the files, so we just return the array
         $createThumbnailsForSizesNode->stmts = (new ParserFactory())->create(ParserFactory::PREFER_PHP7)
-            ->parse('<?php if ($thumbnailSizes->count() === 0) {
+            ->parse('<?php if ($thumbnailSizes === null) {
+                                return [];
+                            }
+
+                            if ($thumbnailSizes->count() === 0) {
                                 return [];
                             }
 
diff --git a/src/EventListener/ThumbnailSizesChangedListener.php b/src/EventListener/ThumbnailSizesChangedListener.php
new file mode 100644
index 0000000..f2171cc
--- /dev/null
+++ b/src/EventListener/ThumbnailSizesChangedListener.php
@@ -0,0 +1,65 @@
+<?php declare(strict_types=1);
+
+namespace Frosh\ThumbnailProcessor\EventListener;
+
+use Shopware\Core\Content\Media\Aggregate\MediaFolder\MediaFolderEntity;
+use Shopware\Core\Content\Media\Aggregate\MediaFolderConfigurationMediaThumbnailSize\MediaFolderConfigurationMediaThumbnailSizeDefinition;
+use Shopware\Core\Content\Media\Commands\GenerateThumbnailsCommand;
+use Shopware\Core\Framework\DataAbstractionLayer\EntityRepository;
+use Shopware\Core\Framework\DataAbstractionLayer\Event\EntityWrittenEvent;
+use Shopware\Core\Framework\DataAbstractionLayer\Search\Criteria;
+use Shopware\Core\Framework\DataAbstractionLayer\Search\Filter\EqualsAnyFilter;
+use Symfony\Component\Console\Input\ArrayInput;
+use Symfony\Component\Console\Output\NullOutput;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+class ThumbnailSizesChangedListener implements EventSubscriberInterface
+{
+    public function __construct(
+        private readonly GenerateThumbnailsCommand $generateThumbnailsCommand,
+        private readonly EntityRepository $mediaFolderRepository,
+    ) {
+    }
+
+    public static function getSubscribedEvents(): array
+    {
+        return [
+            MediaFolderConfigurationMediaThumbnailSizeDefinition::ENTITY_NAME . '.written' => 'onThumbnailSizeChanged',
+            MediaFolderConfigurationMediaThumbnailSizeDefinition::ENTITY_NAME . '.deleted' => 'onThumbnailSizeChanged',
+        ];
+    }
+
+    public function onThumbnailSizeChanged(EntityWrittenEvent $event): void
+    {
+        $updatedMediaFolderConfigurationIds = [];
+
+        foreach ($event->getWriteResults() as $writeResult) {
+            $mediaFolderConfigurationId = $writeResult->getPayload()['mediaFolderConfigurationId'] ?? null;
+
+            if (!empty($mediaFolderConfigurationId) && \is_string($mediaFolderConfigurationId)) {
+                $updatedMediaFolderConfigurationIds[] = $mediaFolderConfigurationId;
+            }
+        }
+
+        $updatedMediaFolderConfigurationIds = \array_unique($updatedMediaFolderConfigurationIds);
+
+        if (empty($updatedMediaFolderConfigurationIds)) {
+            return;
+        }
+
+        $criteria = new Criteria();
+        $criteria->addFilter(new EqualsAnyFilter('configurationId', $updatedMediaFolderConfigurationIds));
+
+        $result = $this->mediaFolderRepository->search($criteria, $event->getContext());
+
+        /** @var MediaFolderEntity $entity */
+        foreach ($result->getEntities() as $entity) {
+            $parameters = [];
+
+            $parameters['--async'] = null;
+            $parameters['--folder-name'] = $entity->getName();
+
+            $this->generateThumbnailsCommand->run(new ArrayInput($parameters, $this->generateThumbnailsCommand->getDefinition()), new NullOutput());
+        }
+    }
+}
diff --git a/src/Resources/config/services.xml b/src/Resources/config/services.xml
index c3bbd3b..836324b 100644
--- a/src/Resources/config/services.xml
+++ b/src/Resources/config/services.xml
@@ -30,5 +30,11 @@
             <argument type="service" id="request_stack"/>
             <argument type="service" id="product_export.repository"/>
         </service>
+
+        <service id="Frosh\ThumbnailProcessor\EventListener\ThumbnailSizesChangedListener">
+            <argument type="service" id="Shopware\Core\Content\Media\Commands\GenerateThumbnailsCommand"/>
+            <argument type="service" id="media_folder.repository"/>
+            <tag name="kernel.event_subscriber"/>
+        </service>
     </services>
 </container>