Hi!  I've been running into an odd issue when using resize() on tiling images, and I was wondering if anyone could help me out?

I'm writing a simple 2D map editor, using square tiles.  I'm trying to convert it from colored squares to tiled images, but the more copies of a particular image I use, the darker all of that image becomes, creating a strong gradient across all instances of that image on the entire map. If I disable the call to the resize function, the gradient issue disappears, but then, the tiles are the wrong size at most of the zoom levels.

The code is below - there're some bits that might look a bit odd.  I've stripped out a lot of stuff for question to make it easier to see what's going on in my code, which is why there's a lot of switch statements with only one case.  The resize function is being called in drawGrid.  The tiles are simple 25 x 25 pixel .bmps.  They don't need to be anything special: a flat colored square achieves the same effect.

1. //Map variables
   int tall, wide;
   int[][] myMap;
   int mapSizeX;
   int mapSizeY;
   String[] newMap;
   int penColor=7;
   int toolSetting = 1;
   boolean editMode = true;
   PVector viewPort;
   float tileSize;
   int startX, startY;
   
   
   void setup() {
     size(1000, 740);
     frameRate(30);
   
     //setup map
     mapSizeX = 51;
     mapSizeY = 51;
     myMap = new int[mapSizeX][mapSizeY];
     initializeMap();
     tileSize = 10;
     wide = int(450/tileSize);
     tall = int(450/tileSize);
     viewPort = new PVector (0, 0);
   }
   
   
   
   void draw()
   {
     // background(255);
   
     if (mousePressed)
     {
       int findX = (int)((mouseX-265)/tileSize) ;
       int findY = (int)((mouseY-41)/tileSize) ;
   
       if ((mouseX > 265 && mouseX < width - 255) && (mouseY > 41 && mouseY < 442))
       {
         println("Mouse coords: " + (mouseX - 265) + ", " + (mouseY - 41));
         println("Map coords: " + findX + ", " + findY);
       }
     }
   
     fill(255);
     rect(206, 18, 40, 20); //Turn counter
     fill(0);
   
     drawGrid();
   }
   
   void mousePressed()
   {
     int findX = (int)(mouseX-265)/(int)tileSize  +(int)viewPort.x;
     int findY = (int)(mouseY-41)/(int)tileSize  +(int)viewPort.y;
     if (mouseButton == LEFT)
     {
   
       myMap[findX][findY] = penColor;
     }
   }
   
   void mouseDragged()
   {
     int findX = (int)(mouseX-265)/(int)tileSize +(int)viewPort.x;
     int findY = (int)(mouseY-41)/(int)tileSize +(int)viewPort.y;
   
     if (mouseButton==LEFT)
     {
       if (editMode == true && findX < wide+viewPort.x && findX >= 0 && findY < tall+viewPort.y && findY >= 0)
       {
         switch(toolSetting)
         {
         case 1:
           myMap[findX][findY] = penColor;
           break;
         }
       }
     }
   }
   
   
   
   
   
   
   void initializeMap()
   {
     for (int i = 0; i <= 50; i++)
     {
       for (int j = 0; j <= 50; j++)
       {
         myMap[i][j] = 9;
       }
     }
   }
   
   
   void drawGrid()
   {
     stroke(1);
     PImage stoneTile = loadImage("tiles/stonefloor.bmp");
     for (int i = 0; i < wide; i++)
     {
       for (int j = 0; j < tall; j++)
       {
         if (i+viewPort.x < mapSizeX && i+viewPort.x >= 0 && j+viewPort.y < mapSizeY && j+viewPort.y >= 0)
         {
           if (myMap[(i+(int)viewPort.x)][(j+(int)viewPort.y)] == 7)
           {
             stoneTile.resize((int)tileSize,(int)tileSize);
             image(stoneTile, 265+i*tileSize, 41+j*tileSize);
           }
   
           else
           {
             fill(getColor(myMap[(i+(int)viewPort.x)][(j+(int)viewPort.y)]));
             rect(265+i*tileSize, 41+j*tileSize, tileSize, tileSize);
           }
         }
       }
     }
   
   }
   
   
   void zoomLevel(int zoom) {
     println(zoom);
     switch (zoom)
     {
     case 0:
       tileSize = 10;
       break;
     case 1:
       tileSize = 15;
       break;
     case 2:
       tileSize = 18;
       break;
     case 3:
       tileSize = 25;
       break;
     }
     wide = int(450/tileSize);
     tall = int(450/tileSize);
     if (viewPort.x + wide > mapSizeX)
     {
       viewPort.x = 0; 
     }
       if (viewPort.y + tall > mapSizeY)
     {
       viewPort.y=0;
     }
   }
   
   color getColor(int theColor)
   {
     int fillColor = color(0, 0, 0);
     switch (theColor)
     {
   
     case 9:
       fillColor = color(255);
       break;
     }
     return fillColor;
   }
   
   

Any help I can get will be greatly appreciated.