Image downsampling bug

[gkouros]

The bug occurs when parameter downsample is set to >1 and it is located on the following line:
https://github.com/half-potato/nmf/blob/3ef13e798a27e8c06d6186b87b0354044faad050/dataLoader/blender.py#L162C1-L163C1

To solve it the image should be read with Pillow (uncomment line 158 + comment out line 159) to be able to use the resize operation with the argument Image.LANCZOS. Otherwise, the argument should be removed since it's undefined for the resize function of numpy arrays.