I'm trying to understand how layout_width/height when sets to "wrap_content", "goes" together with scaleType? AFAIK, scaleType (let's say 'center_fit') responsible of scaling up or down image size, but when width or height is set to wrap_content, isn't it means that the width & height of the ImageView will be calculated from the image (drawable) size? So why in this situation, the drawable will be scaled at all?
scaleType defines how you want your image to appear in the case that the width and height isn't match / appropriate e.g. fitCenter makes it centered and fit, while fitXY stretches it if it has spaces.