In my opinion, coding is easier then graphics, maybe takes a little longer, but graphics and stories are something that take creativity. Coding is just words that you can basically copy and paste.
Okay, a bit of advice. Never ever ever say this to a developer. Software engineering, which is what we're really talking about here, is a complex dance of mental gymnastics, that takes careful planning, design, and intelligent programming to bring a product to life. People go to college for it, and/or spend years learning it. You could program for fifty years, and still not know it all. It is 100% about creativity. I am a software engineer in the day, and make iPhone games at night. Any good software product involves massive amounts of planning and design, and that involves creativity. The coding involves finding solutions to simple and complex problems, all of which involves creativity. At no point in my day am I blindly copy and pasting anything. Heck, out of the 8-12 hours a day that I develop software, only 1-2 hours of it involves typing code.
Both of my games are highly profitable on the App Store, and I did all the design, code, and graphics myself, so I know all sides of the process. The design of my first game took a couple weeks. The coding took several months of evening work. And the graphics took a week. If I were to price out the development time, I'd say it cost about $20,000. If I had outsourced the graphics to an artist, they would've been paid around $1,000. When you say, "coding is just words that you copy and paste," that is equivalent to saying doctoring is just giving pills to patients, after you look up the symptoms in a book. There's a reason most developers make six figure incomes. It's hard, and not a lot of people can do it.
That being said, yes, the graphics are simply referenced from various locations in the code, and can be replaced within seconds with different graphics. Your best bet is to either hire a novice programmer to work with you, as they may be willing to work for profits. If you're looking for an experienced programmer, you're looking at minimum $150 per hour, or 75% of the profits.