Build Shopify Appstore App

A Shopify App Store App that lets stores install a size-responsive banner on their website that can display icons they have chosen in the app dashboard. Users that install the app on their store will be able to come to the app dashboard and add, remove and rearrange the images/icons from our pre-existing list of images to build the banner that will be displayed on their site. The display of the app dashboard should be very simple with a gallery of small images, that can be dragged and dropped from the gallery to the preview "canvas" Selected images will display in a rendered strip banner above with the gallery, where they can rearrange or drag off to remove. There will be a maximum limit of 6 images that can be selected. The images should resize relative to each other to fit the banner best. The banner will also resize to fit the container and be responsive to it's div/containter. Installing the app will place the dynamic banner snippet or iframe somewhere on their theme. We are seeking a developer with experience with Shopify API and specifically building or working with Shopify App Store apps. They must also be able to build the database that will house the customer settings and where we can manage which images are loaded into the gallery to choose from.