I find the site easy to use, and it loads each page very quickly even though there are lots of images on the pages which is important to me as a user.
The large picture on the home page that cycles through a sampling of the images is very nice, and provides a good preview of what is to come.
It is a bit unclear to me why the payment information is on the first page, when there is no mention of purchasing at that stage. I would put the payment information on the purchase page, or include on the first page that some items are available for purchase. Currently the site appears to be more of a display of the work as opposed to a sales site. That said, the process of selecting the image, type of print and number of copies is very easy to do and would not inhibit the purchase process. I appreciate that there is an easy to access and easy to use contact form, so if the client had any questions they could easily reach someone for help.
Some text on the log in page indicating that it is for clients with accounts with the artist (I'm assuming that is what it is for) would clarify in what circumstances you would need to log in. Right now I don't know what to do with it, or how to make an account (or if an account is needed.)
I am not so fond of the font, and would prefer something a bit more modern, that provides more distinction between the titles (like "Feature Galleries") and the subtitles ("Western Canada" "France" etc.) The size of the font is excellent and makes the website easy to read.
The navigation bar at the top of the screen is very clear, and it makes the site easy to navigate.
Regarding the layout of the photos and galleries, I appreciate that they fit easily into the browser window and do not require a lot of scrolling to see all of them. I would, however, organize them differently purely for aesthetics (align the centers horizontally, and put the single landscape in between the two portrait, for example).
Overall a solid website that is easy to use.