function getImagePaths(folder)

    dirs = dir.getdirectories(folder);

    imagePaths = {}

    for i,dirpath in ipairs(dirs) do

        command = 'find ' .. dirpath .. ' -iname "*.png"'

        res = sys.execute(command)

        for str in string.gmatch(res, "([^\n]+)") do

            table.insert(imagePaths, str)

        end

    end

    return imagePaths

end