How can I make all pictures to vertically align?

I am attaching my data set and code also. I want to correct all images orientation and want to make them all vertically align. I have tried this. But my code not going to be the general one. For few images I am not able to correct their orientation. Actually I want the fingers parts to be the upside.

if true
  clc;
close all;
clear;
workspace;
folder = pwd;
% folder = pwd;
filepattern = fullfile(folder, '*.png');
srcFiles = dir(filepattern);
numImages = length(srcFiles);
for k = 1 : numImages
  fullFileName = fullfile(folder, srcFiles(k).name);
a = imread(fullFileName);
bwimg =bwareafilt(~a, 1); 
s=regionprops(bwimg,'Orientation');
theta = s.Orientation;
if theta>=0 && theta<90 
phi=90-theta;
Y=imrotate(bwimg,phi);
else
phi=90+theta;
Y=imrotate(bwimg,-phi);
end
end

[KALYAN ACHARJYA]

Do you want to rotate the complete image?

[Zara Khan]

Yes. Will you able to help me ??please then