Android & ios App graphic designer, Wanted!!

Hi Guys & Girls We have created a simple app, that were selling to a small niche market. The design part has previusly been done by our programmer. Were looking for someone who can modify our app each time, so it will match our customers website identity. Its minor modifications(insert logo, colour change ect) The basic design of the App, will always stay the same. The candidate were looking for, will be able to make those simple design changes on both the android and ios version. Our programmer wil code it. Consider in your bid, that each design will only take max 1 hour due to the the fact the app is very simple. You must be able to start no later than jan 4. We constantly 3 apps behind.