Provided you have created a category for that monument then I would recommend just looking at the category, and if you have several images for a monument it makes sense to put them all in one category. If you have a matching article on Wikipedia you can then link the whole lot via a {{commonscat}}
Here is a category I created today http://commons.wikimedia.org/wiki/Category:Conderton_Hill_Fort
Using the standard Commons interface rather than a specific tool has several advantages, not least that it is the way a very large proportion of users will use it.
WSC