Passing an image file name is now mandatory, before that the user could
be induced into thinking that a command like the following was sending
an image:
 ./picoproj -W 800 -H 480 -F 1 some_image.jpg
while the actually intended command line was:
  ./picoproj -W 800 -H 480 -F 1 -f some_image.jpg
                                ^^
Note the missing -f in the first command line.
        int opt;
 
        char filename[FILENAME_MAX] = {0};
        int opt;
 
        char filename[FILENAME_MAX] = {0};
+       int image_fd;
+       struct stat st;
        am7xxx_device dev;
        int format = AM7XXX_IMAGE_FORMAT_JPEG;
        int width = 800;
        int height = 480;
        am7xxx_device dev;
        int format = AM7XXX_IMAGE_FORMAT_JPEG;
        int width = 800;
        int height = 480;
-       uint8_t *image = NULL;
-       unsigned int size = 59475;
+       uint8_t *image;
+       unsigned int size;
 
        while ((opt = getopt(argc, argv, "f:F:W:H:h")) != -1) {
                switch (opt) {
 
        while ((opt = getopt(argc, argv, "f:F:W:H:h")) != -1) {
                switch (opt) {
 
-       if (filename[0] != '\0') {
-               struct stat st;
-               
-               image_fd = open(filename, O_RDONLY);
-               if (image_fd < 0) {
-                       perror("open");
-                       exit_code = EXIT_FAILURE;
-                       goto out;
-               }
-               if (fstat(image_fd, &st) < 0) {
-                       perror("fstat");
-                       exit_code = EXIT_FAILURE;
-                       goto out_close_image_fd;
-               }
-               size = st.st_size;
+       if (filename[0] == '\0') {
+               fprintf(stderr, "An image file MUST be specified.\n");
+               exit_code = EXIT_FAILURE;
+               goto out;
+       }
-               image = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, image_fd, 0);
-               if (image == NULL) {
-                       perror("mmap");
-                       exit_code = EXIT_FAILURE;
-                       goto out_close_image_fd;
-               }
+       image_fd = open(filename, O_RDONLY);
+       if (image_fd < 0) {
+               perror("open");
+               exit_code = EXIT_FAILURE;
+               goto out;
+       }
+       if (fstat(image_fd, &st) < 0) {
+               perror("fstat");
+               exit_code = EXIT_FAILURE;
+               goto out_close_image_fd;
+       }
+       size = st.st_size;
+
+       image = mmap(NULL, st.st_size, PROT_READ, MAP_SHARED, image_fd, 0);
+       if (image == NULL) {
+               perror("mmap");
+               exit_code = EXIT_FAILURE;
+               goto out_close_image_fd;
 
        am7xxx_shutdown(dev);
 
 out_munmap:
        am7xxx_shutdown(dev);
 
 out_munmap:
-       if (image != NULL) {
-               ret = munmap(image, size);
-               if (ret < 0)
-                       perror("munmap");
-       }
+       ret = munmap(image, size);
+       if (ret < 0)
+               perror("munmap");
-       if (image_fd >= 0) {
-               ret = close(image_fd);
-               if (ret < 0)
-                       perror("close");
-       }
+       ret = close(image_fd);
+       if (ret < 0)
+               perror("close");