how to convert set of images into a single .mat file .

I have 6 folders and each folder has 400 images . I am able to convert a single image into a mat file . for every image am getting a separate mat file . I need to work on single mat file for all those images . I am here with attaching the files the output i got and the output i need . Please help me

[Walter Roberson]

You have a series of rgb images but you appear to be asking for the result to be a single 2d array. What should be done with the color information? When the images are spliced together should it be horizontally or vertically?

[Bhagavathula Meena]

Thank you for response . I need all features of a single image to be vertical . Every row to be represented as features of one image . If i have 200 images then 200 rows to be represented as features of every individual image . the matrix to be save as tensor . I have gray scale and rgb images separately stored in different folders .

[Image Analyst]

OK but what are the "features" you extracted? Like mean, standard deviation, mean diameter of particles in the image, number of foreground objects, some texture metrics, or the presence or absence of some target? What? Exactly what are these "features"? Do you have a numerical vector listing all the feature values you have measured from the image? Can you attach one of the feature vectors in a .mat file? Are you sure all images will have the same number of features?