diff --git a/avwmaths.c b/avwmaths.c
index 6271177fad8464e86c4bc29132653d3bfe73893c..e78f17f8973e402d52894d214f6e20e21a1a4421 100644
--- a/avwmaths.c
+++ b/avwmaths.c
@@ -146,9 +146,9 @@ double tmpd;
 
 {
   image_struct tmpim=im;
-  tmpim.i=malloc(size*sizeof(FDT));
   float percfrac=0.5;
   int doperc=0;
+  tmpim.i=malloc(size*sizeof(FDT));
 
   if (!strncmp(argv[i]+2, "perc", 4))
     {