After running a search, your results will be displayed in a Thumbnail mode, displaying a thumbnail with title, creator and date information in the caption. You can also display results in larger thumbnal mode, which displays additional information with larger thumbnail images, by clicking on the third icon located under the Advanced Search link in the upper right of the page, next to the navigation arrows. You can also do this by clicking on the "Display large thumbnails" option under the "Display options" tab at the top of page.
Use the navigation arrows on the upper right to scroll through the images displayed in your search.
You can SORT your results, in either Thumbnail or List Mode, by Creator, Title or Date. Simply click on Title, Creator, or Date on the top left of your results screen. The date refers to the creation date of the object, and the sort order is date ascending.
Clustering: ARTstor clusters duplicate images. The image that is the first within the cluster, and hence connoted as the authoritative copy, is either a Museum contribution, or an image that is determined to be empirically better than other copies of that image residing within ARTstor. To view all copies of an image, click on the + icon (mousing over this icon, you will see the words: "Click to display related images") next to the image in your results list.
More on viewing images in ARTstor (from the ARTstor Help wiki)