minor changes

image.c

@@ -26,6 +26,10 @@ void read_until_space_or_newline(char * buff, int maxCount, FILE * fptr){
 
 Image * load_pgm_image(char * image_file_string){
     FILE * fptr = fopen(image_file_string, "r");
+    if(!fptr){
+        printf("could not open image file. exit\n");
+        exit(1);
+    }
     Image *image = malloc(sizeof(Image));
     image->label = -1;
 

main.c

@@ -23,7 +23,7 @@ void parsingErrorTrain(){
 
 void parsingErrorDetect(){
     printf("invalid syntax\n");
-    printf("Syntax: c_net predict_demo [path_to_network] [image_file]");
+    printf("Syntax: c_net predict_demo [path_to_network] [image_file]\n");
 }
 
 void predict_demo(int argc, char** arguments){