I'm trying to read in a large number of jpg files using a for loop. But for some reason, the k index is not advancing. I just get A as a 460x520x3 uint8. Am I missing something? My goal with this code is to convert all the jpg images to the same size. Since I haven't been able to advance through the images, I can't quite tell if I'm doing it right. nFrames = length(date); % Number of frames. for k = 1:nFrames-1 % Number of days % Set file under consideration A = imread(['map_EUS_' datestr(cell2mat(date_O3(k)),'yyyy_mm_dd') '_O3_MDA8.jpg']); % Size of existing image A. [rowsA, colsA, numberOfColorChannelsA] = size(A); % Read in and get size of existing image B (the next image). B = imread(['map_EUS_' datestr(cell2mat(date_O3(k+1)),'yyyy_mm_dd') '_O3_MDA8.jpg']); [rowsB, colsB, numberOfColorChannelsB] = size(B); % Size of B does not match A, so resize B to match A's size. B = imresize(B, [rowsA colsA]); eval(['print -djpeg map_EUS_' datestr(cell2mat(date_O3(k)),'yyyy_mm_dd') '_O3_MDA8_test.jpg']); end end