Unity UI [HorizontalLayoutGroup] Image RectTransform size is bigger than the "actual" image

Hello everybody.

I'm trying to create a UI from script.
I want to build a simple structure like this:

-> Container (Horizontal Layout Group)
--> image_0
--> image_1
--> ...

My images are all different in terms of dimensions.
When Unity puts the images into the Horizontal Layout Group gameobject, it often happens that the image itself has a lower size than its rect transform (as you can see in the picture, the "zero" image is preserving its aspect as desired, but the height is stretching until the end of the parent height):



I need the rect transform to be the same width and height of the image, so that the container can fit on its children in a correct way, but I can't figure out where to access these information.

Also, I don't understand how to make it work with the "Child Control Height" of Horizontal Layout Group. Apparently I can't deselect it, or my images' height value in rect transform will be 0. So, even if I had the "correct" image height, I couldn't set it on its rect transform.

Thanks in advance for any suggestion.

 

Ok I found out the solution. I'll leave it here just for the sake of completion.
I've put all my loading code inside a coroutine, then when I create the container I uncheck "Child Control Height" and manually set the height, since I know its width (but only after WaitForEndOfFrame(), otherwise the sizeDelta will be (0,0)).