diff --git a/src/LegacyThumbnailMigrationHelper.php b/src/Dev/Tasks/LegacyThumbnailMigrationHelper.php
similarity index 98%
rename from src/LegacyThumbnailMigrationHelper.php
rename to src/Dev/Tasks/LegacyThumbnailMigrationHelper.php
index f8df1a1b..aa3dbcba 100644
--- a/src/LegacyThumbnailMigrationHelper.php
+++ b/src/Dev/Tasks/LegacyThumbnailMigrationHelper.php
@@ -1,11 +1,12 @@
 <?php
 
-namespace SilverStripe\Assets;
+namespace SilverStripe\Assets\Dev\Tasks;
 
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
-use SilverStripe\Assets\FilenameParsing\LegacyFileIDHelper;
+use SilverStripe\Assets\File;
 use SilverStripe\Assets\Flysystem\FlysystemAssetStore;
+use SilverStripe\Assets\Folder;
 use SilverStripe\Core\Config\Configurable;
 use SilverStripe\Core\Environment;
 use SilverStripe\Core\Injector\Injectable;
diff --git a/tests/php/LegacyThumbnailMigrationHelperTest.php b/tests/php/Dev/Tasks/LegacyThumbnailMigrationHelperTest.php
similarity index 96%
rename from tests/php/LegacyThumbnailMigrationHelperTest.php
rename to tests/php/Dev/Tasks/LegacyThumbnailMigrationHelperTest.php
index a40356a7..09f237a0 100644
--- a/tests/php/LegacyThumbnailMigrationHelperTest.php
+++ b/tests/php/Dev/Tasks/LegacyThumbnailMigrationHelperTest.php
@@ -1,19 +1,17 @@
 <?php
 
-namespace SilverStripe\Assets\Tests;
+namespace SilverStripe\Assets\Tests\Dev\Tasks;
 
 use Silverstripe\Assets\Dev\TestAssetStore;
 use SilverStripe\Assets\File;
-use SilverStripe\Assets\FileMigrationHelper;
+use SilverStripe\Assets\FilenameParsing\FileIDHelperResolutionStrategy;
 use SilverStripe\Assets\FilenameParsing\ParsedFileID;
 use SilverStripe\Assets\Filesystem;
-use SilverStripe\Assets\Flysystem\FlysystemAssetStore;
 use SilverStripe\Assets\Folder;
 use SilverStripe\Assets\Image;
-use SilverStripe\Assets\LegacyThumbnailMigrationHelper;
+use SilverStripe\Assets\Dev\Tasks\LegacyThumbnailMigrationHelper;
 use SilverStripe\Assets\Storage\AssetStore;
-use SilverStripe\Assets\Tests\FileMigrationHelperTest\Extension;
-use SilverStripe\Core\Config\Config;
+use SilverStripe\Assets\Tests\Dev\Tasks\FileMigrationHelperTest\Extension;
 use SilverStripe\Core\Convert;
 use SilverStripe\Dev\SapphireTest;
 
@@ -49,7 +47,7 @@ public function setUp()
         TestAssetStore::activate('LegacyThumbnailMigrationHelperTest/assets');
 
         // Ensure that each file has a local record file in this new assets base
-        $from = $this->joinPaths(__DIR__, 'ImageTest/test-image-low-quality.jpg');
+        $from = $this->joinPaths(__DIR__, '../../ImageTest/test-image-low-quality.jpg');
         foreach (File::get()->exclude('ClassName', Folder::class) as $file) {
             /** @var $file File */
             $file->setFromLocalFile($from, $file->generateFilename());
diff --git a/tests/php/LegacyThumbnailMigrationHelperTest.yml b/tests/php/Dev/Tasks/LegacyThumbnailMigrationHelperTest.yml
similarity index 100%
rename from tests/php/LegacyThumbnailMigrationHelperTest.yml
rename to tests/php/Dev/Tasks/LegacyThumbnailMigrationHelperTest.yml