I've done it by myself.
here is the solution, and it works perfectly.
NSData* imageData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:
[[self.articlesArray objectAtIndex:indexPath.row]objectForKey:@"images"]]];
UIImage* image = [[UIImage alloc] initWithData:imageData];
cell.imageView.image =image;