WHY AM I HAVING TO PUT THE ENTIRE FILE PATH?!?!

Ok im using netbeans and everytime i try input a file or anything i have to put the whole file path...which means none of my programs will be universal. example:

File file = new File("mgmt.jpg");

doesn't work...ever. even when mgmt.jpg is in netbeans in my project folder in my list of files under my java package.

File file = new File("C:/Users/Cameron Hussey/Documents/NetBeansProjects/pic2text/src/pic2text/mgmt.jpg");

i have to put this...which means noone can use my project.

why is this happening? this is something that shouldn't even be a problem , that noone should ever have to post on a forum about. but apparantly i do...any ideas guys? here is my whole code...it's a picture2text converter.

Code Java:

package pic2text;
 
import java.io.*;
import java.awt.*;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
 
public class pic2text {
 
    public static void main(String args[]) throws IOException {
        BufferedImage image = null;
 
        File file = new File("mgmt.jpg");
 
        if (file.exists()) {
            image = ImageIO.read(file);
        } else {
            System.out.println("doesn't exist man");
        }
 
        int w;
        int h;
        int clr = 0;
        String xline = null;
        String chars = null;
 
        for (h = 0; h < image.getHeight(); h+=2) {
 
            //System.out.println(clr);
 
            for (w = 0; w < image.getWidth(); w+=2) {
 
                clr = image.getRGB(w, h);
 
                switch (clr / -1350000) {
                    case 0:
                        chars = "$";
                        break;
                    case 1:
                        chars = "$";
                        break;
                    case 2:
                        chars = "@";
                        break;
                    case 3:
                        chars = "@";
                        break;
                    case 4:
                        chars = "%";
                        break;
                    case 5:
                        chars = "%";
                        break;
                    case 6:
                        chars = "H";
                        break;
                    case 7:
                        chars = "#";
                        break;
                    case 8:
                        chars = "#";
                        break;
                    case 9:
                        chars = "*";
                        break;
                    case 10:
                        chars = "*";
                        break;
                    case 11:
                        chars = "+";
                        break;
                    case 12:
                        chars = "+";
                        break;
                    case 13:
                        chars = "-";
                        break;
                    case 14:
                        chars = "-";
                        break;
                    case 15:
                        chars = ".";
                        break;
                    case 16:
                        chars = ".";
                        break;
 
                }
 
                xline = xline + chars;
 
            }
 
            System.out.println(xline);
            xline = null;
        }
 
    }
}