You can use a stringstream to get that:

#include <sstream>
std::stringstream s;
s << "image-" << i;
image[i] = al_load_bitmap(s.str().c_str());

You do have to check if the image loaded, but he wanted to know how to get those file-names correct.

I use this for my pacman game to load in my main character. He is on a sprite sheet which is basically just a group of images, all 50x50 each, 4 wide x 5 high.

   pacman.sheet = al_load_bitmap("Graphics/Pacman.png");
   if(!pacman.sheet) {
      a5_error(AT, display.screen, "Failed to load Pacman bitmaps.");
      shut_down();
      exit(1);
   }
   for(int y = 0; y < 5; y++) {     // bitmaps are 5 rows
      for(int x = 0; x < 4; x++) {  // by 4 columns
         pacman.bitmap[4*y+x] = al_create_sub_bitmap(pacman.sheet, x*SPRITE_SIZE, y*SPRITE_SIZE,
                                                     SPRITE_SIZE, SPRITE_SIZE);
      }
   }

I have a function called shut_down(); that will destroy any bitmaps that were created. I don't like just exiting my program on error without first calling that to properly destroy anything that may have been created before the error.

Anyhow, this way you load in the graphics all at once, then you can procede to create subbitmaps of each image you want if they're all related (and small enough to fit on a single sheet).

Arthur: how will <code>image[num] = al_load_bitmap("images/image-"".jpg");</code> know what image number to load?!
I see you corrected that.

I have always done it like: (C code, I actually use C99 myself)

Also, when I save images like that, I like to name them with 3 numbers, like IMAGE000.JPG, IMAGE001.JPG ... IMAGE287.JPG, they will list in your directory in order this way... in which case you want to use something like:

sprintf(filename, "images/image%03d.jpg", i);

this is the simplest code i have used for loading 8 audio samples in my program.

ALLEGRO_SAMPLE *sample[8];
  ALLEGRO_SAMPLE_INSTANCE *sample_instance[8];
  char path[30] = "data\\samples\\sample (0).wav";

  for (int i = 0; i < 8; i++)
  {
    // i replace the char 22 of the path, result: sample(i).wav
    path[21] = '0'+(i + 1); // the '0' is just for implicit conversion
    cout << path << endl;
    sample[i] = al_load_sample(path);
    sample_instance[i] = al_create_sample_instance(sample[i]);
    al_set_sample_instance_gain(sample_instance[i], samples_volume);
    al_set_sample_instance_playmode(sample_instance[i], ALLEGRO_PLAYMODE_ONCE);
    al_attach_sample_instance_to_mixer(sample_instance[i], al_get_default_mixer());
  }