diff --git a/app/services/card_image_loading_service.rb b/app/services/card_image_loading_service.rb
index f7dd2d8..a0c3afe 100644
--- a/app/services/card_image_loading_service.rb
+++ b/app/services/card_image_loading_service.rb
@@ -33,9 +33,10 @@ def import_disk(disk)
     logger.info("Fetching disk #{disk} file list")
     filenames = disk_array(disk)
     progress_bar.total += filenames.count
-    Sync do |task|
+    Sync do
+      semaphore = Async::Semaphore.new(100)
       filenames.map do |file_name|
-        task.async do
+        semaphore.async do
           progress_bar.increment
           find_or_create_card_image(file_name)
         end