MATLAB: How to reconstruct a original 2D image from the 1D matrix

reconstruction of image

upto now I convert 2D image into 1D image matrix.I want to reconstruct into 2D image.I have a struggle on this.can you please help me?

You need to reshape your 1D vector into mXn matrix. Have a look on reshape function.

By using reshape function:

A=randi([1 6],1,10); %demo data
reshape(A,2,[])

image = imread('Image.bmp');
y = dct(image);
help dct

help dct2

in matlab will give you a better idea.