Spectra Gallery is full-featured. The page you are on now is the Album. Within the album, you can have an unlimited number of Galleries, each with an unlimited number of photos. By styling the Album you decide how you want everything to look. You select the size of the thumbnails and image holders and how the image holders will look. Spectra Gallery comes with a sample gallery to help you when you build your own.
You can build as many pages as you need and they will be added to the menu you choose.
Of course, anytime you are working with images, the important aspect of compressing all of those images stands out. The best tool I have run is Caesium, a free desktop image compressor.
You can get Caesium here.
The Album page is flexible. You can choose to have a page with sidebars or articles or both.
As the administrator when you are logged in to your site you have the ability to edit content without having to leave the page that you are on. Click the edit icon to open the editor. Make any changes you want and save them. It's quick and easy.
Spectra Gallery comes with 6 premade themes but by using the powerful theme builder you can edit them or build your own.