insert image into table and retrieve from the database to grid-view ....and insert image into binary format in table, not stored in folder... using c# asp.net

     hi every one,
     insert image into table and retrieve from the database to grid-view ....and image insert into binary format in table,
      not stored in folder... using c# asp.net...
    actually i am using stored image into folder but same filename image problem.. suppose i have already image logo.png
then if another user also have same logo.png then old one deleting new one is in the folder.. both user getting same logo.png

hope your getting my problem 

thank you very much in advance