Why is my output B&W?

So im working on this project where I have to load the image1, select 10 points and save the cropped image to a folder. But im having problems with it because my output is showing B&W.. And also it only saves a black image with a white mark in it. How can I fix this? thanks

function save1_Callback(hObject, eventdata, handles)

 a = imread('image1.jpg');
 imshow(a);
 [r c]=ginput(10);
 bg = roipoly(a,r,c);
 [R C] = size(bg);
 for i=1:R
     for j=1:C
         if bg(i,j)==1
             Out(i,j)=a(i,j);
         else
             Out(i,j)=0;
         end
     end
 end
 figure;
 imshow(Out,[]);
 imwrite(Out, 'C:\Users\Image Lab 2\Documents\MATLAB\ crop1.jpg');

Answer 1

[Image Analyst]

You're just getting 10 locations and Out is a monochrome image - it's not an RGB image, and you're just assigning it a value of either 0, or the value at linear index or your RGB image, which will be the wrong pixel. And I don't see any cropping going on. What do you want to do? Do you want to crop it or mask it to the polygon of 10 points? See my attached masking demos.