These length of codes are supported to do when every time a key is pressed, a letter and associated image are shown on the screen.  Plus, when another key is pressed, the previous letter and image are hidden.

Thanks for the comments, but I still cannot get each key pressed letter to correspondent to each image.


PFont font;
char letter = 'a';  
int maxImages = 26; // Total # of images
int imageIndex = 1; // Initial image to be displayed is the first
PImage img;

void setup()  
{
size(500, 500);
smooth();
font = loadFont("Candara-Bold-80.vlw");  
textFont(font);
textSize(100);  
 
img = loadImage("image1.gif");
img = loadImage("image2.gif");
img = loadImage("image3.gif");
img = loadImage("image4.gif");
img = loadImage("image5.gif");
img = loadImage("image6.gif");
img = loadImage("image7.gif");
img = loadImage("image8.gif");
img = loadImage("image9.gif");
img = loadImage("image10.gif");
img = loadImage("image11.gif");
img = loadImage("image12.gif");
img = loadImage("image13.gif");
img = loadImage("image14.gif");
img = loadImage("image15.gif");
img = loadImage("image16.gif");
img = loadImage("image17.gif");
img = loadImage("image18.gif");
img = loadImage("image19.gif");
img = loadImage("image20.gif");
img = loadImage("image21.gif");
img = loadImage("image22.gif");
img = loadImage("image23.gif");
img = loadImage("image24.gif");
img = loadImage("image25.gif");
img = loadImage("image26.gif");
}

void draw()
{
  background(173, 180, 216);  
  text(letter, 30, 90);  
   
  for(int i = imageIndex; i < maxImages; i +=1)
  {
    imageMode(CENTER);
    image(img, 264, 298);
   }    
}

void keyPressed()  
{
  if(key >= 'A' && key <= 'z')
    {
     letter = char(key);
     println(key);
    }
}