So you class a website...
where customers can upload their own photos (up to 30MB photos), manipulate those photos into a final design with different product options whilst interactively showing a preview of the final design, then order their custom products with advanced ecommerce features such as onsite card processing and shipping calculated on size, weight, country, not even considering what the website backend system is (fulfilment, order processing) etc...
... as a
simple website?
Underestimating the complexity of a problem, is IMO, one of the main reasons why software development projects fail, overrun, go overbudget, or run into problems. Forrester Research place it at
number 5 in their top 10 reasons why software development projects fail.
That Forrester Research article mentions software development mistakes, but from my experience it almost always starts off as a client problem. The client thinks it is simple, and they therefore choose a supplier who also says that it is simple, because the supplier response matches their initial expectations, and more importantly budget, regardless of whether it is correct or not.
Even the description I have given of your website requirements above may sound simple, but the devil is always in the detail. Complexity exists in even the most simplest of things.
Forget software, websites and IT systems, even a simple thing like giving instructions to make a cup of tea is complex when you consider all possible eventualities (it is not just a case of "put the kettle on and make a cup of tea", if kettle is empty add water, which tap to use to fill the kettle, what if there is no water coming from the tap, once water is in kettle switch kettle on, what if kettle does not switch on, ... what cup, what tea, what if there is no tea, what if teabag breaks, what sugar... etc).
There are top developers out there. But does it not make sense that the top developers get to pick and choose their clients?
If you were a top developer would you choose a client who thinks everything you do should be easy, one who disagrees with you when you tell them that in fact it is complicated? Or would you choose a client who listens to you, respects you, and trusts your judgement?
I would suggest that you need something similar in user order functionality to that site only. Is that site a business success? Does it do well on the search engines (for targeted terms like photos on canvas)? Does it make much money? If not, then you really don't want something too similar to that particular site.