diff --git a/kitty/dnd.c b/kitty/dnd.c
index 4a1857bd7..d389de492 100644
--- a/kitty/dnd.c
+++ b/kitty/dnd.c
@@ -1396,8 +1396,8 @@ drag_add_image(Window *w, unsigned idx, int fmt, int width, int height, int opac
         img.opacity = opacity;
         base64_init_stream_decoder(&img.base64_state);
     }
-    if (img.capacity < MAX(32, sz + img.sz)) {
-        size_t newcap = MAX(img.capacity * 2, MAX(32, sz + img.sz));
+    if (img.capacity < MAX(32u, sz + img.sz)) {
+        size_t newcap = MAX(img.capacity * 2, MAX(32u, sz + img.sz));
         uint8_t *tmp = realloc(img.data, newcap);
         if (!tmp) abrt(ENOMEM);
         img.data = tmp;