The problem is that you are creating a new image each time the draw method is executed and these all take up memory which is not being released fast enough by the JVM (Java virtual machine).

Is the image changing constantly? If not then you might do this.

1. // put this outside of the functions draw and setup so it is global
2. PGraphics scaleMap;
   

and inside setup() create the image

1.      scaleMap= createGraphics(spriteW, spriteH, JAVA2D);

and inside draw()

1. if(newSpriteW !=  spriteW || newSpriteH != spriteH)
2. {
   
3.       scaleMap.beginDraw();
4.       scaleMap.image(scaleImage, 0, 0, spriteW, spriteH);
5.       scaleMap.endDraw();
6.       spriteW = newSpriteW;
7.       spriteH = newSpriteH;
8.       System.gc(); // optional but requests a garbage collection
   
9. }
   

newSpriteW and newSpriteH are used to store the new size for the sprite.

This assumes that scaleImage is the original image!

I also assume that later in the draw method you are drawing scaleMap to the display, if the only thing you need to do is display scaleImage at a particular position (say px, py) with a particular size then this can be done with the image() method i.e.

1. image(scaleImage, px, py, spriteW, spriteH);

This would replace the code in the draw() method.

Thanks for your reply :)