This is a gallery, created with the default WordPress Gallery Option. The Image size of gallery pics is set automatically when the theme is activated, all you have to do then is to insert a gallery with link to image to make it look like the one bellow.
Order: (string) (Optional) ASC or DESC.
Orderby: (string) (Optional) The default is “menu_order”. “RAND” (random) is also supported.
Id : (string) specify the post ID. The gallery will display images which are attached to that post.
Columns : (string) specify the number of columns. The gallery will include a break tag at the end of each row, and calculate the column width as appropriate. The default value is 4.