In your GeoGalleries dashboard, you can sort them in various ways, such as newest, last updated, rank, etc.
In your personal GeoGalleries site (youusername.geogalleries.com), they will always be displayed by rank (which you control in the dashboard by dragging the image to where you want it to be), followed by newest. These will be displayed in descending order. So the higher the rank, the closer to the top.
If the main geogalleries site (geogalleries.com) and the categories are displayed in newest first.
Categories:
Geo Galleries
Geo Galleries Artists