The images in the Commons search results are not properly aligned. This is due to some CSS in their MediaWiki:Common.css, which is not yet adapted to the changes made in T320295: Special:Search should not use <table>.

It's not entirely clear how that CSS worked before, so that has to be figured out before we can repair.
What is known is that their:
.searchResultImage-thumbnail .image img
should become
.searchResultImage .searchResultImage-thumbnail img

There is also a block

.searchResultImage .searchResultImage-thumbnail {
    width: initial;
    height: initial;
}

which doesn't seem like a super good idea in combination with the new code...

I also noticed that core doesn't take account of the image border.