The implicit conversion of the nvarchar data type into varbinary (max) is not allowed. Use the CONVERT function to perform this query

Follow the code below:

byte[] image1 = ConvertTo.Bytes(Request.Files[0]);
byte[] image2 = null;

ctx
.Users
.Where(x => x.Id == 1)
.Update(x => new User()
{
    ImageByte1 = image1,
    ImageByte2 = image2
});

I use this here: link

Only the problem if I set null to ImageByte2 . Here is an error:

  

The implicit conversion of the nvarchar data type into varbinary (max) does not   is allowed. Use the CONVERT function to execute this query

Now your self set ImageByte1 and ImageByte2 as null , does update normally or ImageByte1 and ImageByte2 other than null also does update.

Any solution?