Popover squashes images and collapses width on narrow notes

[sub-atomic]

Two issues I've noticed with the page preview popover.

1. If you hover over a link to an image file, the image will be squashed to fit inside the dimensions of the popover. A 500 x 800 px image will be squashed to 400 x 300 px.
2. If you have content that does not use the full width of the note, such as a narrow table, the scrollbar for the popover of that note will be shifted toward the left, with empty space to the right.

These two issues are not present in other themes, but I really like this theme and would love to see these bugs resolved.