infolder = '' % give the path of the folder where your RGB images are present
outfolder = '' % give the path of the folder where you want to save gray images
imgFiles = dir([infolder,filesep,'\*.png']) ; % give extension of your images
N = length(imgFiles) ; % total images in the foder
for i = 1:N
thisFile = [infolder,filesep,imgFiles(i).name] ; % each image file
[filepath,name,ext] = fileparts(thisFile) ; % get name of the image file and extension
outFile = [outfolder,filesep,[name,ext]] ; % write gray image file on this name here
I = rgb2gray(imread(thisFile)) ; % reac and conver RGB image into gray
imwrite(I,outFile) ; % write the gray image in the said folder on the name
end
