HOG features for Image Data store

I typed the same code of digit classification i change the datastore only by another images but their sizes are not equal, Is that problem ? numImages = numel(trainingSet.Files); trainingFeatures = zeros(numImages, hogFeatureSize, 'single');

for i = 1:numImages img = readimage(trainingSet, i);

    img = rgb2gray(img);

    % Apply pre-processing steps
    img = imbinarize(img);

    trainingFeatures(i, :) = extractHOGFeatures(img, 'CellSize', cellSize);  
end

% Get labels for each image. trainingLabels = trainingSet.Labels;

Subscripted assignment dimension mismatch.

Error in Untitled3 (line 119) trainingFeatures(i, :) = extractHOGFeatures(img, 'CellSize', cellSize);