it's the drawText() call in node class that draws the text. and the text is parsed from the file and passed into node constructor.

i'd set up a (hashmap) mapping from all your a values to the associated image. load all the images during setup. either do a lookup during the draw or at the same time text is set.

actually, you could just have an image for each a value, named after the a value - 22.png, back3.png... then loadImage() this file in the node constructor and store it there. replace drawText() with image(); (this does need you to know all the image names in advance)

in node change the following functions:

 private PImage img;      // new member
 node(float ix, float iy, String iText) {
    x = iy;
    y = ix;
    text = iText;
   
    inputs = new ArrayList();
    outputs = new ArrayList();
   
    //need to draw the font before we can know and set the width
    textFont(fontA);
    text(text, x, y);

    img = loadImage(text + ".png"); // will fail if not there. but that's ok.
    if (img != null) {
      // use image size
      width = img.width + 2;
      height = img.height + 2;
    } else {   
      width = textWidth(text) + 2 * border;
      height =  -1 * (boxHeight + 2 * border);
    }
    setXY();
  }

and

  private void drawText()
  {
    if (img != null) {
      // use image
      image(img, round(x + 1), round(y + 1));
    } else {
      // text
      fill(textColor);
      textFont(fontA);
      text(text, textX, textY);
    }
  }

now you need to add a graphic for each node to the data directory. needs to be a png and have the exact same name as the node, 22.png, top.png, frontBezel.png, etc. they don't all need to be there - i used 3 in testing.

image nodes aren't dragable. not sure why not.

Thanks so much Koogy, I'll try this when I get back to work on monday and let you know if I have any further problems - I really appreciate your help on this /pauric

Update: works beautifully! thanks.  I'm now trying to figure out why the drag is broken...

much appreciated /pauric

Update2: curiously changing
height = img.height + 2;
to
height = -1* (img.height + 2 ) ;
enables the text box and dragging, but only when modifying height, not width..