Asp.Net Wep Api 2 Error When Posting Json Object - asp.net

Question

I'm developing 3 simple RESTFul services by using ASP.NET Web API 2 and EF6
The name of first service is ImageGallery, which returns ImageGallery json object from Database
I have two entities like these:
ImageGalley.cs:
public class ImageGallery
{
[Key]
public int ID { get; set; }
public string Name { get; set; }
public virtual ICollection<Image> Images { get; set; }
}
And Also, Image.cs:
public class Image
{
[Key]
public int ID { get; set; }
public int ImageGalleryID { get; set; }
public string Caption { get; set; }
public string Url { get; set; }
public virtual ImageGallery ImageGallery { get; set; }
}
My Controller's Get method:
public IList<ImageGallery> GetImageGalleries()
{
var imgGalls = db.ImageGalleries.ToList();
return imgGalls;
}
For Post:
[ResponseType(typeof(ImageGallery))]
public IHttpActionResult PostImageGallery(ImageGallery imageGallery)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.ImageGalleries.Add(imageGallery);
db.SaveChanges();
return CreatedAtRoute("DefaultApi", new { id = imageGallery.ID }, imageGallery);
}
I have put this line of code in my Global.asax to avoid self referencing loop:
GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
I'm using POSTMAN to get and post Json Objects. But when i'm trying the Post, i encounter that error.
{
"Message": "The request is invalid.",
"ModelState": {
"imageGallery": [
"Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'MobileApis.Models.ImageGallery' because the type requires a JSON object (e.g. {\"name\":\"value\"}) to deserialize correctly.\r\nTo fix this error either change the JSON to a JSON object (e.g. {\"name\":\"value\"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List<T> that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.\r\nPath '', line 1, position 1."
]
}
}
Here is my GET Response:
[
{
"Images": [
{
"ID": 3,
"ImageGalleryID": 1,
"Caption": "Image 1",
"Url": "http://placehold.it/350x150"
},
{
"ID": 4,
"ImageGalleryID": 1,
"Caption": "Image 2",
"Url": "http://placehold.it/350x150"
},
{
"ID": 5,
"ImageGalleryID": 1,
"Caption": "Image 3",
"Url": "http://placehold.it/350x150"
},
{
"ID": 6,
"ImageGalleryID": 1,
"Caption": "Image 4",
"Url": "http://placehold.it/350x150"
}
],
"ID": 1,
"Name": "Image Gallery 1"
}
]
I will be so happy, if you help me.