Background images for an Android App

We are soon aiming to launch our game App on Android. We are planning on making multiple Apps sharing the theme. We need help on designing graphics. At this point we need five different background images. The theme will be snowy/winter landscape. You will be given some guidelines and an example of an animated character moving on the background. The images need to support multiple screen sizes and aspect ratios. The images should be done along the published best practices. You need to own all the copyrights. After full-payment all the copyrights will be transferred to us.