A mockup isn't as easy to create as you may think
To some people, design is an art, to others, design is a technical showpiece of engineering. I believe that that good design is a solid mixture of both but before I explain, let me introduce myself. My name is Toby and I am a graphics designer at Massive Splash and I am responsible for crafting Photoshop images which I pass on to the development team for them to build a website on. You can think of me as the engineer that is responsible for creating a blueprint that is effective and feasible.
Before I create a Photoshop Layout or a "Mock Up", I first have a conversation with an ICT consultant who is responsible for being the point of contact with the client. The ICT consultant usually has a completed Project Assessment form which the client has to complete and it is comprised of 4 pages worth of questions. My goal is to turn a business idea into an image and believe me its not as easy as it sounds.
First I have to take into consideration all the business requirements. A E-Commerce platform functions very differently from a Real Estate listings website. Second, I have to take into consideration what the client likes in terms of colors, layout and to what degree of interactivity the website will have (rotating backgrounds, flash movies etc). Third, I have to take into consideration the budget the client has in mind and the feasibility of my design. I can craft the most stunning piece of artwork that would rival any in the industry but would be useless if my colleagues in the development team took years to make and subsequently cause the client to wonder if the project will ever be completed.
The above is a very simplistic view of how a mockup is constructed, so the next time you recieve a mockup, know that some graphics designer poured a lot of love, headaches and time into creating it!