How to remove outer spacing & layout flicker

1. I noticed that the gallery is not aligned with the rest of the content because of each thumbnail’s outer padding.
Would it be possible to add an option that applies negative margin to the left and right side to cancel that padding? (Only makes sense when using transparent background though) I tried to use a simple custom CSS, but it seems like the width needs to be recalculated somehow to prevent the gallery from just shifting to the left side.

2. When loading the thumbnails they have no height at first, showing the page content from below for a fraction of a second. With each element already having a width and height specified, maybe this can be avoided?

Thanks in advance!