lets say I have a table with three images whose `accessiblityIdentifier` set to "fooImage".

`XCTAssertTrue(table["tableName"].images.count == 3)` will work, but this is sucky -- what if someone adds another image type? I want the count of all the images whose identifier == "fooImage".

`XCUIApplication().images["fooImage"].count` is a compile fail with `Value of type 'XCUIElement' has no member 'count'`.