Please, put [ code ] and [ /code ] tags around your code (without the spaces).

A few notes on your code:

 if(frame<f+5)
  draw_sprite(buffer, (BITMAP*)A[x].dat, 0, 0);
  masked_blit(buffer, screen, 0, 0, 175, 72, buffer->w, buffer->h);//Blit the buffer
  clear_bitmap(buffer);//Clear the buffer

It looks like you want some brackets for that if statement, depending on the speed that speed_counter is incremented it looks like the picture should flicker a lot or even not appear at all. Heres the code with some brackets.

 if(frame<f+5) {
  
  draw_sprite(buffer, (BITMAP*)A[x].dat, 0, 0);
  masked_blit(buffer, screen, 0, 0, 175, 72, buffer->w, buffer->h);//Blit the buffer
  clear_bitmap(buffer);//Clear the buffer
 }

You probably want to call the 'blit' function instead of the 'masked_blit' function. Unless you're doing some crazy effect with your buffer, you can make your game run make faster and respond more smoothly by replacing it with a blit. Heres how I would write the chunk of code you wrote:

 if(frame<f+5) {
  
  draw_sprite(buffer, (BITMAP*)A[x].dat, 0, 0);
  blit(buffer, screen, 0, 0, 175, 72, buffer->w, buffer->h);//Blit the buffer
  clear_bitmap(buffer);//Clear the buffer
 }

You also probably want to blit the buffer to the screen at 0,0. Heres the final code:

 if(frame<f+5) {
  
  draw_sprite(buffer, (BITMAP*)A[x].dat, 0, 0);
  blit(buffer, screen, 0, 0, 0, 0, buffer->w, buffer->h);//Blit the buffer
  clear_bitmap(buffer);//Clear the buffer
 }

Nobody answered your question because you didn't ask a question.

Neither your original comments, nor your code snippet make it clear what you are really trying to do, or what the problem is. If you want help, you need to help others by clearly describing the problem, and what you are trying to achieve.