A conditional tag that displays its contents if the asset in context is the first item in the row in context when publishing a grid of assets (e.g. thumbnails). Grid of assets can be created by specifying assets_per_row attribute value to Assets block tag.
For example, the first, the fourth and the seventh asset are the first assets in row when Assets iterates eight assets and assets_per_row is set to "3".
<table> <mt:Assets type="image" assets_per_row="4"> <mt:AssetIsFirstInRow><tr></mt:AssetIsFirstInRow> <td><$mt:AssetThumbnailLink$></td> <mt:AssetIsLastInRow></tr></mt:AssetIsLastInRow> </mt:Assets> </table>