diff --git a/apps/theming/appinfo/info.xml b/apps/theming/appinfo/info.xml
index fcdaade0fd5..402ea9f0ba2 100644
--- a/apps/theming/appinfo/info.xml
+++ b/apps/theming/appinfo/info.xml
@@ -31,6 +31,9 @@
 		<pre-migration>
 			<step>OCA\Theming\Migration\MigrateUserConfig</step>
 		</pre-migration>
+		<post-migration>
+			<step>OCA\Theming\Migration\InitBackgroundImagesMigration</step>
+		</post-migration>
 	</repair-steps>
 
 	<commands>
diff --git a/apps/theming/lib/Jobs/MigrateBackgroundImages.php b/apps/theming/lib/Jobs/MigrateBackgroundImages.php
new file mode 100644
index 00000000000..97806fa600a
--- /dev/null
+++ b/apps/theming/lib/Jobs/MigrateBackgroundImages.php
@@ -0,0 +1,107 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2022 Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Theming\Jobs;
+
+use OCA\Theming\AppInfo\Application;
+use OCP\App\IAppManager;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJobList;
+use OCP\BackgroundJob\QueuedJob;
+use OCP\Files\AppData\IAppDataFactory;
+use OCP\Files\NotFoundException;
+use OCP\Files\NotPermittedException;
+use OCP\IConfig;
+
+class MigrateBackgroundImages extends QueuedJob {
+	public const TIME_SENSITIVE = 0;
+
+	private IConfig $config;
+	private IAppManager $appManager;
+	private IAppDataFactory $appDataFactory;
+	private IJobList $jobList;
+
+	public function __construct(ITimeFactory $time, IAppDataFactory $appDataFactory, IConfig $config, IAppManager $appManager, IJobList $jobList) {
+		parent::__construct($time);
+		$this->config = $config;
+		$this->appManager = $appManager;
+		$this->appDataFactory = $appDataFactory;
+		$this->jobList = $jobList;
+	}
+
+	protected function run($argument): void {
+		if (!$this->appManager->isEnabledForUser('dashboard')) {
+			return;
+		}
+
+		$themingData = $this->appDataFactory->get(Application::APP_ID);
+		$dashboardData = $this->appDataFactory->get('dashboard');
+
+		$userIds = $this->config->getUsersForUserValue('theming', 'background', 'custom');
+
+		$notSoFastMode = \count($userIds) > 5000;
+		$reTrigger = false;
+		$processed = 0;
+
+		foreach ($userIds as $userId) {
+			try {
+				// precondition
+				if ($notSoFastMode) {
+					if ($this->config->getUserValue($userId, 'theming', 'background-migrated', '0') === '1') {
+						// already migrated
+						continue;
+					}
+					$reTrigger = true;
+				}
+
+				// migration
+				$file = $dashboardData->getFolder($userId)->getFile('background.jpg');
+				try {
+					$targetDir = $themingData->getFolder($userId);
+				} catch (NotFoundException $e) {
+					$targetDir = $themingData->newFolder($userId);
+				}
+				if (!$targetDir->fileExists('background.jpg')) {
+					$targetDir->newFile('background.jpg', $file->getContent());
+				}
+				$file->delete();
+			} catch (NotFoundException|NotPermittedException $e) {
+			}
+			// capture state
+			if ($notSoFastMode) {
+				$this->config->setUserValue($userId, 'theming', 'background-migrated', '1');
+				$processed++;
+			}
+			if ($processed > 4999) {
+				break;
+			}
+		}
+
+		if ($reTrigger) {
+			$this->jobList->add(self::class);
+		}
+	}
+}
diff --git a/apps/theming/lib/Migration/InitBackgroundImagesMigration.php b/apps/theming/lib/Migration/InitBackgroundImagesMigration.php
new file mode 100644
index 00000000000..c23a9176843
--- /dev/null
+++ b/apps/theming/lib/Migration/InitBackgroundImagesMigration.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2022 Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @author Arthur Schiwon <blizzz@arthur-schiwon.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Theming\Migration;
+
+use OCA\Theming\Jobs\MigrateBackgroundImages;
+use OCP\BackgroundJob\IJobList;
+use OCP\Migration\IOutput;
+
+class InitBackgroundImagesMigration implements \OCP\Migration\IRepairStep {
+
+	private IJobList $jobList;
+
+	public function __construct(IJobList $jobList) {
+		$this->jobList = $jobList;
+	}
+
+	public function getName() {
+		return 'Initialize migration of background images from dashboard to theming app';
+	}
+
+	public function run(IOutput $output) {
+		$this->jobList->add(MigrateBackgroundImages::class);
+	}
+}
diff --git a/apps/theming/lib/Service/BackgroundService.php b/apps/theming/lib/Service/BackgroundService.php
index 0614fe00357..36623735728 100644
--- a/apps/theming/lib/Service/BackgroundService.php
+++ b/apps/theming/lib/Service/BackgroundService.php
@@ -30,6 +30,7 @@ namespace OCA\Theming\Service;
 use InvalidArgumentException;
 use OC\User\NoUserException;
 use OCA\Theming\AppInfo\Application;
+use OCP\Files\AppData\IAppDataFactory;
 use OCP\Files\File;
 use OCP\Files\IAppData;
 use OCP\Files\IRootFolder;
@@ -133,20 +134,22 @@ class BackgroundService {
 	private IAppData $appData;
 	private IConfig $config;
 	private string $userId;
+	private IAppDataFactory $appDataFactory;
 
 	public function __construct(
-		IRootFolder $rootFolder,
-		IAppData $appData,
-		IConfig $config,
-		?string $userId
+		IRootFolder     $rootFolder,
+		IAppDataFactory $appDataFactory,
+		IConfig         $config,
+		?string         $userId
 	) {
 		if ($userId === null) {
 			return;
 		}
 		$this->rootFolder = $rootFolder;
-		$this->appData = $appData;
+		$this->appData = $appDataFactory->get(Application::APP_ID);
 		$this->config = $config;
 		$this->userId = $userId;
+		$this->appDataFactory = $appDataFactory;
 	}
 
 	public function setDefaultBackground(): void {
@@ -193,6 +196,11 @@ class BackgroundService {
 			try {
 				return $this->getAppDataFolder()->getFile('background.jpg');
 			} catch (NotFoundException | NotPermittedException $e) {
+				try {
+					// Fallback can be removed in 26
+					$dashboardFolder = $this->appDataFactory->get('dashboard');
+					return $dashboardFolder->getFolder($this->userId)->getFile('background.jpg');
+				} catch (\Throwable $t) {}
 			}
 		}
 		return null;