Lumbermatt

I forgot : The color #1d1d1d is the color of the very thin 1px border around the thumbnails. To get the border away, just change the line to border: 0px;

Here are two examples of usage of this css :
https://snag.fr/?p=389
https://snag.fr/?p=312

Hope that this help anybody.

Here is the definitive code to :
1 – Get all thumbnails on one line (to avoid the last thumbnail being “pushed” to next row)
2 – Get ride of the (ugly) big white borders around the thumbnails
3 – Center the thumbnails (when mixing landscape and portrait thumbnails, or with different aspect ratio).

Tested in Firefox 22, Safari 5 and Chrome 28 (not in IE… if somebody want to test it).

.ngg-gallery-thumbnail img {
    padding: 0px;
    border: 1px solid #1d1d1d;
    margin: 4px auto;
}

.ngg-gallery-thumbnail {
    width: 100%;
    margin-left: auto;
    margin-right: auto;
}

.ngg-gallery-thumbnail-box {
    text-align: center;
    margin: 0px;
}

For number 1, try this out : https://www.ads-software.com/support/topic/solution-for-messed-up-thumbnails.

For 2… at the same URL there’s a solution but which works not Firefox (actually).

Other information for those who might be interested.

When mixing landspace and portrait pictures, the portrait pictures are not centered but on the left of the thumbnail div which doesn’t look very nice.

To center everything, just go to WP Admin Panel, Gallery > Other Options > Styles > (Show Customization Options) and edit the css file :

.ngg-gallery-thumbnail-box {
    margin: 0px auto;   <-- For the previous edit in the first post
    text-align: center;
}

.ngg-gallery-thumbnail {
    float: center;
    display: inline-block;
}

Note : This actually works in Safari en IE *but* not Firefox. We are working on it to get this to work.

The thumbnails have a fat white border around which looks really ugly. To get ride of them, just add following code to the same file :

.ngg-gallery-thumbnail img {
    padding: 0px;
    border: 1px solid #1d1d1d;
    margin: 4px auto;
}

In this example, the border is reduced to a very thin 1 pixel border with the color #1d1d1d. To customize the color juste change #1d1d1d to what ever you want. To get ride of the border, change 1px to 0px.

jesse, I had the same problem. Look here : https://www.ads-software.com/support/topic/solution-for-messed-up-thumbnails