I'm trying to write a program that will take a JPG image, change some bytes of the image code, and re-output the new image. I was able to accomplish this in one way:

1.  
2. byte b[];
3. int start = 4000;
4. int step = 200;
5. 
   
6. void setup() {
7. size(1000, 612);
8. b = loadBytes("sourceImage.jpg"); 
9. }
10. 
    
11. void draw() {  
12. for(int i = start; i<start+step; i++) {
13.   b[i] = 0;
14. }
15. start+=step;
16. 
    
17. saveBytes("output.jpg", b);
18. PImage img = loadImage("output.jpg");
19. image(img,0,0);
20. }

However, as I understand, this will not work if I want to use this program as a web application because it won't have permissions to save an image to the computer, which I do in line 17. Could anyone give me advice on how to get around this - either by modifying my code to use something other than saveBytes to change my JPG, or by finding a permissions workaround?

Thanks!

Keenan