How to construct image representation after applying low pass and high filter along the coloum using the dwt2 and before performing downsampling?

I am applying a discrete wavelet transformation on an image(suppose of size512*512) .

according to the theory first the low and high filter is applied on the image along the column. then the image is down sampled by a factor of 2. then again one low pass and one high pass filter is applied one each of the above two along the row this time. Again down sampled. Then we obtain 4 subband images after level 1 decomposition(approximation, horizontal,vertical and diagonal details) each of size 256*256.

But the fact is that when first low and high pass filter is applied along the column. Then I want to construct image representation from these low pass and high filtered components. Actually I want to construct two images one from the low pass filter component and one from the high pass filtered component.