RGBY Images dataset

I am working on Human Protein Atlas competiton on kaggle . There are RGBY images in dataset. I am combining the RGBY images using cv to an array. I want to create an image of thi s input array and return it in get_x function or maybe pass this array directly. I don’t know how to do that. Please help.

     colors = ['red','green','blue','yellow']
     flags = cv2.IMREAD_GRAYSCALE
     img = [cv2.imread(fname+'_'+color+'.png', flags).astype(np.float32)/255
            for color in colors]
    np.stack(img, axis=-1)

I haven’t tried this competition, but I took a look at the competition and found this sample notebook which used fastai. In it they describe how they dealt with RGBY. Hope it helps:
https://www.kaggle.com/iafoss/pretrained-resnet34-with-rgby-0-460-public-lb

This is for old version of fast.ai.