def METHOD_NAME(self):
    for ratio in self.params.objects('disk_change_ratio'):
        for idx, tag in enumerate(self.src_img_tags):
            image_params = self.params.object_params(tag)
            block_size = int(self.src_img_sizes[idx] * float(ratio))
            args = (None, block_size, self.source_images[idx])
            self.main_vm.monitor.block_resize(*args)
            self.check_image_size(self.source_images[idx], block_size)
            self.check_bitmaps(self.source_images[idx], self.bitmaps[idx])