feat: enhance image loading and socket handling in Product and Images components, and update prerender logic in App and ProductDetailPage

src/components/CartItem.js

@@ -20,7 +20,7 @@ class CartItem extends Component {
         this.setState({image:window.tinyPicCache[picid],loading:false, error: false})
       }else{
         this.setState({image: null, loading: true, error: false});
-        if(this.props.socket){
+        if(this.props.socket && this.props.socket.connected){
           this.props.socket.emit('getPic', { bildId:picid, size:'tiny' }, (res) => {
             if(res.success){
               window.tinyPicCache[picid] = URL.createObjectURL(new Blob([res.imageBuffer], { type: 'image/jpeg' }));