Why does the wrap_content in imageview not make it much bigger based on the actual width?

I have an ImageView that has:

android:layout_height="100dp"   
android:layout_width="wrap_content"
android:scaleType="fitCenter" 
android:adjustViewBounds="true"   

What I see is that if I set an image that has as dimensions (based on the info of my pc) 1280px854
If I open it in my pc the image looks huge.
The same image is small in my ImageView although I have set wrap_content.
I am not sure I get how this works. E.g. 1280/4 = 320dpi (xxxhdpi) but for with wrap_content the image view does not have as width 320dpi
To clarify: I am trying to understand why it works like that and does not make it bigger with wrap_content.

First, let's talk about the ratio of your image. It's 1280px wide and 854px tall, hence, its proportion is 1280/854 ≈ 3/2.

Second, you've set the height of your ImageView to 100dp. If the width is not specified, then android will try its best to perceive the ratio (3/2) and will calculate the width:

ratio = width/height
3/2 = width/100
width = 150dp

Notice it gave us dp, if we were to plug px instead(for the height) it will give us px back.

Third, now that we have the size of the image (150dp x 100dp) and width='wrap_content' the width of the imageView will correspond to the 150dp