1 files changed, 2 insertions, 1 deletions

diff --git a/src/image.c b/src/image.c
index 4681cba1f87..144fe30a746 100644
--- a/src/image.c
+++ b/src/image.c
@@ -4615,7 +4615,8 @@ lookup_rgb_color (struct frame *f, int r, int g, int b)
 #elif defined HAVE_NS
   return RGB_TO_ULONG (r >> 8, g >> 8, b >> 8);
 #else
-  eassume (false);
+  xsignal1 (Qfile_error,
+            build_string ("This Emacs mishandles this image file type"));
 #endif
 }