fixed bug where reward image url could not be blank
fixed bug where reward image url could not be blank

studio666/CrowdtiltOpen,prathapsridharan/publicworx-crowdtilt,timchunght/crowdhero,timchunght/crowdhero,lanreayeni/CrowdtiltOpen,lanreayeni/CrowdtiltOpen,studio666/CrowdtiltOpen,Crowdtilt/CrowdtiltOpen,prathapsridharan/publicworx-crowdtilt,brijbhan/crowdtilt,studio666/CrowdtiltOpen,lanreayeni/CrowdtiltOpen,brijbhan/crowdtilt,sapierre/CFP,Crowdtilt/CrowdtiltOpen,timchunght/crowdhero,sapierre/CFP,Crowdtilt/CrowdtiltOpen