Have been using this extension for the first time, before always used SIGE, but wanted to try something else. Very simple in use and works well. But - doesn't look so well with both vertical and horizontal images. Especially non-cropped thumbnails. When you crop vertical thumbnails, which are usually portraits, they get cropped in the middle and that always cuts people's faces off. Nor here, nor in SIGE there is no simple option to crop the top part of the image for the thumbnail.
I also usually prepare images myself, so don't need them to be scaled. Here there is no simple option to leave images unscaled - you have to choose 100% quality and set the vertical size to the size of the images + several pixels, since the gallery adds the border to the images. For example if you have an image size 800x600 px, you'd need to set gallery width to 810 and max. height to 608, then it seems it leaves the original quality of the image.