component:
<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes" controller="pic_ctrl">
    <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
    <aura:attribute name="urls" type="String" />
    
   
       <!--  data: {!v.urls}  -->
        <aura:iteration items="{!v.urls}" var="row">
      <div class="slds-grid  slds-wrap"  style="height: 203px; width:400px ; background-color:white;" onclick="{!c.showcarousel}" >
       <div class="slds-col slds-size_1-of-2">
                      <img src="{!row}"  style="height: 200px; width:400px ; background-color:white;"/>
                             </div>
                    </div>
       </aura:iteration>
</aura:component>

Controller.js
({ 
    doInit : function(component, event, helper) {
            var getdata = component.get("c.geturl");
      		var h = [];
            getdata.setCallback(this, function(response){      
                var state = response.getState();
                if (state === 'SUCCESS'){
                    var Result = response.getReturnValue();
                  
                 //var finalJson = JSON.parse(finalJson1);
                    var len=Result.length;
                  
                    for(var i=0; i<len; i++){
                       
                        h.push(Result[i]["imageURL"]);
                    }
                    
					component.set("v.urls",h);
                  
                }
            });
            $A.enqueueAction(getdata);      
        }
})

Apex class:

public class pic_ctrl {
    @AuraEnabled
    public static Object geturl() {
       
            String ImgJson = ' [        {"imageName": "Mice1.jpg","imageId": "101", "imageURL": "https://labpulse.s3.amazonaws.com/images/images1.jpg", "imageDescription": "Some description" },{"imageName": "Mice2.jpg","imageId": "101", "imageURL": "https://labpulse.s3.amazonaws.com/images/images2.jpg", "imageDescription": "Some description" },' +
       '{ "imageName": "Mice3.jpg","imageId": "102",  "imageURL": "https://labpulse.s3.amazonaws.com/images/images3.jpg", "imageDescription": "Some description" }, {"imageName": "Mice4.jpg", "imageId": "103", "imageURL": "https://labpulse.s3.amazonaws.com/images/images4.jpg",  "imageDescription": "Some description" }]';

		 Object Finaljson= JSON.deserializeUntyped(ImgJson); 
     
        return Finaljson;
    } 
   
   
}