diff --git a/sixel.c b/sixel.c
index 3e13af23..0a01e8b7 100644
--- a/sixel.c
+++ b/sixel.c
@@ -1492,6 +1492,8 @@ sixel_add_ar_11(struct terminal *term, uint32_t *data, int stride, uint32_t colo
     xassert(term->sixel.pos.row < term->sixel.image.height);
     xassert(term->sixel.pan == 1);
 
+    if (data == NULL)
+        return;
     if (sixel & 0x01)
         *data = color;
     data += stride;