diff --git a/src/thumbnail.c b/src/thumbnail.c
index f85e4343df1a5dfa7550660faed012a0d860a886..b4f410d959a350084f7338be7816d8e45f65ea5c 100644
--- a/src/thumbnail.c
+++ b/src/thumbnail.c
@@ -144,6 +144,7 @@ init_thumbnail_mode(void)
    index_image_width = td.w;
    index_image_height = td.h + title_area_h;
    td.im_main = imlib_create_image(index_image_width, index_image_height);
+   gib_imlib_image_set_has_alpha(td.im_main, 1);
 
    if (!td.im_main)
       eprintf("Imlib error creating index image, are you low on RAM?");