diff --git a/coders/aai.c b/coders/aai.c
index bc31f6f..66f0c70 100644
--- a/coders/aai.c
+++ b/coders/aai.c
@@ -373,7 +373,7 @@
     /*
       Allocate memory for pixels.
     */
-    pixels=(unsigned char *) AcquireQuantumMemory((size_t) image->columns,
+    pixels=(unsigned char *) AcquireQuantumMemory(image->columns,
       4*sizeof(*pixels));
     if (pixels == (unsigned char *) NULL)
       ThrowWriterException(ResourceLimitError,"MemoryAllocationFailed");