Fix a small overallocation of memory.

src/image.c

@@ -223,7 +223,7 @@ image **load_alphabet()
 {
     int i, j;
     const int nsize = 8;
-    image **alphabets = calloc(nsize, sizeof(image));
+    image **alphabets = calloc(nsize, sizeof(image*));
     for(j = 0; j < nsize; ++j){
         alphabets[j] = calloc(128, sizeof(image));
         for(i = 32; i < 127; ++i){