2 column lay out - Image does not take full height of it container

I had created a 2 column layout - 1 text column, 1 image column.

The image is set to 100%, and its 2000 px 2000px. At first, it takes 100% of its container, but when I add more content to the second column (and therefor - expanding the height) - The image does not take the full height and width of its container.

I am using WordPress btw.

I attach an image - to show my example. Link to image

*Both of the columns are in the same container/section.

First example - Image is taking 100% of its container.

Second example - Adding more content to the next column - making it higher :

The image remains the same height.

How can I fix it, making the image take 100% of its container even If I adding more content?