diff --git a/coders/icon.c b/coders/icon.c
index 81879dd..8d6bfa4 100644
--- a/coders/icon.c
+++ b/coders/icon.c
@@ -861,7 +861,7 @@
   next=image;
   do
   {
-    if ((next->columns == 256) && (next->rows == 256))
+    if (next->compression == ZipCompression)
       {
         Image
           *write_image;