Hi there,
Scaling background images when there is content inside the container ( ie. the post title ) is tricky.
If there was no content you could set the Top and Bottom padding as a % unit, to equal the aspect ratio of your image. For example your image is 782px(H) x 1174(W) divide the two and multiply by 100:
782 / 1174 * 100 = 66%.
Setting the top padding to 33% and bottom padding to 33% ( total 66% ) will maintain the original images aspect ratio.
As there is content inside the container you would need to tweak these values down a little. eg 30%. It won’t be 100% perfect but will get you closer to the mark.
Alternatively if you want to keep using Pixel padding, you can select the Mobile icon beside the padding and set a lower mobile value.
Ideally you want all your featured images to be the same size ( aspect ratio ).