Hi Mihaela,
For images without captions the padding displays correctly, except that some images including with those with no caption have a transparent box under them, about 15px high running the width of the image and padding and with a faint grey border around it.
On images with captions the padding does not extend down as background for the caption, the upper part of the (black) caption text is covered by the overlay and is grey. The lower part of the caption text outside of the transparent box mentioned above is displayed normally (black).
On another site with different settings, the overlay covering the caption text does not occur (all text is black), but the caption text is moved up to the edge of, or onto the image and the 10px padding. Borders do not show at the bottom of some images and may be a few pixels short of reaching the bottom on the sides.