Gallery blocks have three settings: the number of columns, style and whether or not images should be cropped. The default number of columns is three, and the maximum number of columns is six. If the number of images cannot be divided into the number of columns you have selected, the default is to have the last image(s) automatically stretch to the width of your gallery. In the editor, the image captions can be edited directly by clicking on the image. Select Media File in the Link to field to activate zoom mode.