Hi –
No problem, I am happy to help.
If you only change the height and not the width of an image you’re going to end up with a squished result. Both of these would need adjusted in order for the image to be maintained.
There are instances where this might not be a big deal, maybe if you were working with scenery or something you could float by with only adjusting 1 parameter of the image. But, in this case, we are looking at people so we need to prevent having squished up bodies and faces.
Take a look at the theme details here for reference: https://wordpress.com/theme/lodestar
When scrolling to the bottom of the page you’ll see this note about the image sizing
The recommended Featured Image size is at least 2000 wide by 1200 tall
Try re adding your images at that scale.