save_photo.cpp

static esp_err_t save_photo_numbered()
{
  file_number++;
  Serial.print("Taking picture: ");
  Serial.print(file_number);
  camera_fb_t *fb = esp_camera_fb_get();

  //char *filename = (char*)malloc(21 + sizeof(int));
  char *filename = (char*)malloc(21 + sizeof(file_number));
  sprintf(filename, "/sdcard/capture_%d.jpg", file_number);

  Serial.println(filename);
  FILE *file = fopen(filename, "w");
  if (file != NULL)  {
    size_t err = fwrite(fb->buf, 1, fb->len, file);
    Serial.printf("File saved: %s\n", filename);
  }  else  {
    Serial.println("Could not open file");
  }
  fclose(file);
  esp_camera_fb_return(fb);
  free(filename);
}

static esp_err_t save_photo_dated()
{
  Serial.println("Taking picture...");
  camera_fb_t *fb = esp_camera_fb_get();

  time(&now);
  localtime_r(&now, &timeinfo);
  strftime(strftime_buf, sizeof(strftime_buf), "%F_%H_%M_%S", &timeinfo);

  char *filename = (char*)malloc(21 + sizeof(strftime_buf));
  sprintf(filename, "/sdcard/capture_%s.jpg", strftime_buf);

  Serial.println(filename);
  FILE *file = fopen(filename, "w");
  if (file != NULL)  {
    size_t err = fwrite(fb->buf, 1, fb->len, file);
    Serial.printf("File saved: %s\n", filename);

  }  else  {
    Serial.println("Could not open file");
  }
  fclose(file);
  esp_camera_fb_return(fb);
  free(filename);
}