Thread: can't get Image size.

I'm making an applet game and it would be nice to get the width and height of an image,
but for some reason the function getWidth(ImageObserver) as well as getHeight(ImageObserver) always return -1 for me, I cant find out why, I'm sure the Images are loaded correctly (they can be drawn on the screen), do I have to pass a specific ImageObserver or is there some other mistake?

I've tried my applet class, wich I use for drawing the images, and null, but both return -1.

OK, ill just copy and paste my entire code

import java.awt.*; 
import java.awt.event.*;
import java.applet.*; 
import java.net.*;
import java.io.*;
 
 
 
//the main class
public class mainapplet extends Applet implements Runnable {
	//vars
	public static mainapplet home;
	player you;
	MediaTracker Mt;
	Thread t = null;
	URL Base;
	int tdelay;
	boolean[] keysdown = new boolean[200];
	//object list
	animation Sprite[] = new animation[1000];
	enemy Enemy[] = new enemy[30];
	weapon Weapon[] = new weapon[200];
	bullet Bullet[] = new bullet[600];
	Image Img[] = new Image[100];
	String ImgName[] = new String[100];
	int Imgcount, animcount, bulletcount, enemycount, weaponcount, maskcount;	
	int width,height;
	//Double buffering stuff
	Graphics bgraph;
	Dimension dim;
	Image tempImg;
	mask blub;
 
	//initilization
	public void init(){
		//keys
		for(int a=0;a<200;a++)
		keysdown[a] = false;
		//constants
		tdelay = 1000/60;
		home = this;
		//counters
		animcount = 0;
		Imgcount = 0;
		bulletcount = 0;
		enemycount = 0;
		weaponcount = 0;
		maskcount = 0;
		//stuff...
		Mt = new MediaTracker(this);
		Base = getDocumentBase();
		getImgs("Images/");	
		you = new player(250,150);
		addEnemy(40,0,0);
		//double buffer stuff
		width = 800;
		height = 600;
		dim = getSize();
		tempImg = createImage(dim.width,dim.height);
		bgraph = tempImg.getGraphics();
		//more stuff
		Graphics g = this.getGraphics();
		blub = new mask(Img[0],g);
 
	}
	//start
	public void start(){
		if(t == null){
			t = new Thread(this);
			t.start();
		}
	}
	//loads png images from a directory
	public void getImgs(String directory){
		File dir = new File(directory);
		String[] list = dir.list();
		for(int a=0;a<list.length;a++){
			if(list[a].substring(list[a].length()-4).toLowerCase().compareTo(".png") == 0){
				Img[Imgcount] = getImage(Base,directory+list[a]);
				ImgName[Imgcount] = list[a].substring(0,list[a].length()-4).toLowerCase();
				System.out.println(Imgcount+" "+ImgName[Imgcount]);
				Imgcount++;
			}
		}
		System.out.println("");
	}
	//adds a new sprite
	public animation addSprite(double x, double y, int delay, String[] names){
		Sprite[animcount] = new animation(x,y,delay,names);
		animcount++;
		return Sprite[animcount-1];
	}
	//removes a sprite
	public boolean removeSprite(animation gone){
		for(int a=0;a<animcount;a++){
			if(Sprite[a] == gone){
				animcount--;
				Sprite[a] = Sprite[animcount];
				return true;
			}
		}
		return false;
	}
	//adds a new enemy
	public enemy addEnemy(double x, double y, int type){
		Enemy[enemycount] = new enemy(x,y,type);
		enemycount++;
		return Enemy[enemycount-1];
	}
	//removes an enemy, and its stuff
	public boolean removeEnemy(enemy gone){
		for(int a=0;a<enemycount;a++){
			if(Enemy[a] == gone){
				removeSprite(Enemy[a].sprite);
				for(int b=0;b<Enemy[a].arms.length;b++)
				removeWeapon(Enemy[a].arms[b]);
				enemycount--;
				Enemy[a] = Enemy[enemycount];
				return true;
			}
		}
		return false;
	}
	//adds a new weapon
	public weapon addWeapon(int x, int y,int ammotype, int firetype, int[] delaypattern,boolean repeat, enemy parent){
		Weapon[weaponcount] = new weapon(x,y,ammotype,firetype,delaypattern,repeat,parent);
		weaponcount++;
		return Weapon[weaponcount-1];
	}
	//removes a weapon
	public boolean removeWeapon(weapon gone){
		for(int a=0;a<weaponcount;a++){
			if(Weapon[a] == gone){
				weaponcount--;
				Weapon[a] = Weapon[weaponcount];
				return true;
			}
		}
		return false;		
	}
	//adds a bullet
	public bullet addBullet(double x, double y, int xspeed, int yspeed,int type){
		Bullet[bulletcount] = new bullet(x,y,xspeed,yspeed,type);
		bulletcount++;
		return Bullet[bulletcount-1];
	}
	//removes a bullet
	public boolean removeBullet(bullet gone){
		for(int a=0;a<bulletcount;a++){
			if(Bullet[a] == gone){
				removeSprite(Bullet[a].sprite);
				bulletcount--;
				Bullet[a] = Bullet[bulletcount];
				return true;
			}
		}
		return false;
	}
	//returns the Image number of an image name
	public int getImgNumber(String name){
		name = name.toLowerCase();
		int a;
		for(a=0;a<Imgcount;a++){
			if(ImgName[a].compareTo(name) == 0)
			return a;			
		}
		return -1;
	}
 
	//run
	public void run(){
		try{
			while(true){
				//invoke step action of every object
				if(you != null)
				you.action();
				for(int a=0;a<enemycount;a++)
				Enemy[a].action();	
				for(int a=0;a<weaponcount;a++)
				Weapon[a].action();	
				for(int a=0;a<bulletcount;a++)
				Bullet[a].action();
				repaint();
				t.sleep(tdelay);
			}
		}
		catch(Exception e){
			System.out.println("run fail, "+e);
		}
	}
 
	//double buffer - update override
	public void update(Graphics g){
		paint(g);
	}
	//draw all animated objects
	public void paint(Graphics g){
		bgraph.clearRect(0,0,dim.width,dim.height);
		for(int a=0;a<animcount;a++){
			Sprite[a].draw(g);
		}
		int s = 10;
		if(you != null)
		you.paint();
		g.drawImage(tempImg,0,0,this);
	}
 
	//key bindings
	public boolean keyDown(Event e, int key){
		if(key > 1000)
		key -= 900;
		keysdown[key] = true;	
		return true;
	}
	public boolean keyUp(Event e, int key){
		if(key > 1000)
		key -= 900;
		keysdown[key] = false;	
		return true;
	}
}
 
//player object
class player {
	animation sprite;
	int x,y,armor,shield,hp, width,height;
	public player(int a,int b){
		x = a;
		y = b;
		String[] spr = {"player"};
		sprite = mainapplet.home.addSprite(a,b,100,spr);
		armor = 100;
		shield = 300;
		hp = armor+shield;
	}
	//running stuff, keyactions
	public void action(){
		sprite.x = x;
		sprite.y = y;
		if(mainapplet.home.keysdown[Event.UP-900]){
			if(y > 100)
			y -= 5;
		}
		if(mainapplet.home.keysdown[Event.DOWN-900]){
			if(y < 590)
			y += 5;
		}
		if(mainapplet.home.keysdown[Event.LEFT-900]){
			if(x > 15)
			x -= 5;
		}
		if(mainapplet.home.keysdown[Event.RIGHT-900]){
			if(x < 785)
			x += 5;
		}
		//check if a bullet is hitting
		bullet b;
		for(int a=0;a<mainapplet.home.bulletcount;a++){
			b = mainapplet.home.Bullet[a];
 
		}
	}
	//draw stuff like health bars
	public void paint(){
		mainapplet.home.bgraph.setColor(Color.black);
		mainapplet.home.bgraph.fillRect(0,0,12,mainapplet.home.height);
		mainapplet.home.bgraph.fillRect(mainapplet.home.width-12,0,12,mainapplet.home.height);
		double shieldpart = mainapplet.home.height/shield;
		int rheight = (int)shieldpart;
		if(hp > armor){
			for(int a=0;a<shield;a++){
				Color c = new Color(0,(int)(132*a/shield)+64,(int)(192*a/shield)+64);
				mainapplet.home.bgraph.setColor(c);
				mainapplet.home.bgraph.fillRect(1,(int)(mainapplet.home.height-shieldpart*a),10,rheight);
				if(hp-armor < a)
				break;
			}
		}	
		double armorpart = mainapplet.home.height/armor;
		rheight = (int)armorpart;
		for(int a=0;a<armor;a++){
			Color c = new Color((int)(192*a/armor)+64,(132*a/armor)+16,0);
			mainapplet.home.bgraph.setColor(c);
			mainapplet.home.bgraph.fillRect(mainapplet.home.width-11,(int)(mainapplet.home.height-armorpart*a),10,rheight);			
			if(a > hp)
			break;
		}
	}
}
 
 
//animation object
class animation {
	double x,y;
	int delay,currentdelay,cyclelength,currentimg;
	int[] Imgs;
	//constructor(x,y,delay,images)
	public animation(double a,double b,int c,String[] z){
		x = a;
		y = b;
		delay = c;
		cyclelength = z.length;
		currentdelay = 0;
		currentimg = 0;
		Imgs = new int[cyclelength];
		for(int d=0;d<cyclelength;d++)
		Imgs[d] = mainapplet.home.getImgNumber(z[d]);			
	}
	public void draw(Graphics g){
		mainapplet.home.bgraph.drawImage(mainapplet.home.Img[Imgs[currentimg]],(int)x,(int)y,mainapplet.home);
		currentdelay++;
		if(currentdelay == delay){
			currentdelay = 0;
			currentimg++;
		}
		if(currentimg == cyclelength)
		currentimg = 0;	
	}
}
//enemy object
class enemy {
	int weight,hp,behaviour,type;
	double maxspeed,xspeed,yspeed,x,y;
	animation sprite;
	weapon[] arms;
	//constructor
	public enemy(double a, double b, int c){
		x = a;
		y = b;
		type = c;
		switch(type){
			//enemy 0: slow, weak, low firepower
			case 0:
				String[] imgs = {"enemy_01_01","enemy_01_02"};
				sprite = mainapplet.home.addSprite(x,y,2,imgs);
				xspeed = 0;
				yspeed = 1.7;
				arms = new weapon[1];
				int[] delay = {20,60};
				arms[0] = mainapplet.home.addWeapon(24,34,0,0,delay,true,this);		
			break;
		}
	}
	public void action(){
		sprite.x = x;
		sprite.y = y;
		x += xspeed;
		y += yspeed;
		if(y > 500)
		mainapplet.home.removeEnemy(this);
	}
	public void fire(int weapon){
 
	}
}
//enemy weapon object
class weapon {
	int currentdelay, delaytime, firetype,ammotype,x,y; //x,y relative to its parent
	int[] delaypattern;
	boolean repeat;
	enemy parent;
	//constructor(x,y,ammotype,firetype,delaypattern,repeatpattern?,parent)
	public weapon(int a, int b,int t,int e,int[] delay, boolean r, enemy p){
		x = a;
		y = b;
		ammotype = t;
		firetype = e;
		delaypattern = new int[delay.length];
		delaypattern = delay;
		parent = p;
		currentdelay = 0;
		delaytime = delaypattern[0];
		repeat = r;
	}
	//every turn actions
	public void action(){
		if(delaytime == 0){
			fire(firetype);
			currentdelay++;
			if(currentdelay == delaypattern.length){
				if(repeat){
					delaytime = delaypattern[0];
					currentdelay = 0;
				}				
			}		
			else
			delaytime = delaypattern[currentdelay];	
		}
		delaytime--;
	}
	public void fire(int type){
		switch(type){
			//fire a bullet straight ahead
			case 0:
				mainapplet.home.addBullet(parent.x+x,parent.y+y,0,6,ammotype);	
			break;
		}
	}
}
//bullet object
class bullet {
	double x,y,xspeed,yspeed;
	int power,type;
 
	animation sprite;
	//constructor(x,y,xspeed,yspeed,type)
	public bullet(double a,double b,double c,double d,int e){
		x = a;
		y = b;
		xspeed = c;
		yspeed = d;
		type = e;
		switch(type){
			//standard bullet
			case 0:
				String[] imgs = {"bullet_01_01","bullet_01_02"};
				sprite = mainapplet.home.addSprite(x,y,2,imgs);
				power = 4;
			break;
		}
	}
	//running stuff
	public void action(){
		x += xspeed;
		y += yspeed;
		sprite.x = x;
		sprite.y = y;
		if(y > 600)
		mainapplet.home.removeBullet(this);
	}
 
 
}
 
//image mask
class mask {
	boolean filled[][];
	public mask(Image Img, Graphics g){
		g.drawImage(Img,0,0,mainapplet.home);
		int width = Img.getWidth(mainapplet.home);
		int height = Img.getHeight(mainapplet.home);
		System.out.println(width+","+height);
		/*g.clearRect(0,0,width,height);
		Robot r = null;
		boolean done = false;
		try{
			r = new Robot();			
		}
		catch(Exception e){}
		Color c = r.getPixelColor(0,0);
		Color d;
		g.drawImage(Img,0,0,mainapplet.home);
		filled = new boolean[width][height];
		for(int a=0;a<width;a++){
			for(int b=0;b<height;b++){
				filled[a][b] = true;
				d = r.getPixelColor(a,b);
				if(d == c)
				filled[a][b] = false;				
			}
		}*/
	}
}

right, sorry.
you will need a folder "Images" with 1 png Image in it for it to run.

import java.awt.*; 
import java.applet.*; 
import java.net.*;
import java.io.*;
 
//the main class
public class mapplet extends Applet implements Runnable {
	//vars
	public static mapplet home;
	Image Img[] = new Image[100];
	String ImgName[] = new String[100];
	int Imgcount;	
	URL Base;
	mask testmask;
 
	//initilization
	public void init(){
		Imgcount = 0;
		Base = getDocumentBase();
		getImgs("Images/");	
		Graphics g = this.getGraphics();
		testmask = new mask(Img[0],g);		
	}
 
	//loads png images from a directory
	public void getImgs(String directory){
		File dir = new File(directory);
		String[] list = dir.list();
		for(int a=0;a<list.length;a++){
			if(list[a].substring(list[a].length()-4).toLowerCase().compareTo(".png") == 0){
				Img[Imgcount] = getImage(Base,directory+list[a]);
				Imgcount++;
			}
		}
	}
	public void run(){}
}
 
class mask {
	public mask(Image Img, Graphics g){
		g.drawImage(Img,0,0,mapplet.home);
		int width = Img.getWidth(mapplet.home);
		int height = Img.getHeight(mapplet.home);
		System.out.println(width+","+height);
	}
}

yes, i was still expirimenting with how to get Graphics to paint outside the paint method. This is my first java programming, so it sure has some things that can be improved. About the size: these functions are the functions i think can not be left out.

thank you, this fixed my problem.
the reason i use Applet is that I've never before heard of JApplet... ill check it out.