System opens a new browser window with the preview of the page containing the specified Gallery on a User Site. Pale grey boxes represent the records in the navigation area that are not yet populated.
The system doesn't stretch images that don't fit specified sizes exactly. It set size the images in the way that longest edge is as per specified dimensions and the other one is keeping image proportions. Image has to be centered in the block. It has to work for images in navigation and data display parts.
Some examples:
You have a cell with 100x100 size. You have two images the first one is 200x300, the second one is 200x100.
As a result you will have the first image with 67x100 sizes and 100x50 sizes for the second one. Note that this both images is shown in the 100x100 cell and centered in it.