Easy Photography Portfolio doesn’t do that on purpose.
If you want to categorize your Portfolio – you can do that using Categories. You can then put links to the relevant categories in your menu, for example “Weddings” and “Portraits” could be 2 categories, both with their own URLs site.com/portfolio/category/weddings and site.com/portfolio/category/portraits.
There are other plugins with the gimmicky show/hide portfolio entries features, but that doesn’t work in a real portfolio for photographers that great. It may be of use for some graphic designers, maybe, but in my opinion – a well structured site is a lot better than show/hide filters.
