Is it possible to have the grey gallery ‘inside’ box match the color of the outside white border? Right now, when I move from one image to the next, it reveals a sort of grey inner box along either the top and bottom edges or right and left edges. This happened when I changed ‘fill’ to ‘fit’ for the gallery options.
You can do that by going to “Theme Options” > “Colors” in your Admin Panel. There you need to check “Use custom colors”, and then set a color for “Galleries background color” (see screenshot). In your case that should be “#fbfbfb”. To save the settings, click the “Update” button.