Blob data type is available in Document object. Try using this to store the images :

            Below is the Sample code to save image in Document :

            ------------ VF Page Code -------------

            <apex:page Controller="SaveImgController"

                        <apex:inputFile value="{!propFileBody}" fileName="{!propFileName}" contentType="{!propContentType}"/>

                        <apex:commandButton value="SameImage" action="{!SaveImg}" />

            </apex:page>           

            ------------ Controller Code -------------

            public class SaveImgController

            {

                        public String  propFileName{ get; set; }

                        public Transient Blob propFileBody{ get; set; }

                        public String  propContentType{ get; set; }

                        public void SaveImg()

                        {

                                    Folder fd = [Select id, name From Folder Where name = 'My Personal Documents'];

                                    Document doc = new Document();

                                    doc.Name = propFileName;

                                    doc.Body = propFileBody;

                                    doc.ContentType = propContentType;

                                    doc.Type = propContentType.substring((propContentType.indexOf('/')+1),propContentType.length());

                                    doc.IsPublic = true;

                                    doc.FolderId = fd.id;

                                    Database.SaveResult sr = Database.Insert(doc);

                        }

            }

Hope this helps.