SQL Server 2008 :: Getting Duplicate Data When Connecting To Another Table

I have the following two tables:

CREATE TABLE [MailBox].[Message](
[Id] [bigint] IDENTITY(1,1) NOT NULL,
[SenderId] [bigint] NOT NULL,
[Message] [nvarchar](max) NOT NULL,
[SentDate] [datetime] NOT NULL,
CONSTRAINT [PK_MailBox.Message] PRIMARY KEY CLUSTERED

[Code] ....

I'm building a messaging functionality in to my application, I'm able to insert a message into the database and this message then appears inside the other users inbox. The issue I have it when I click on this message to view the conversation I make a call to the following sp as shown here:

@UserId bigint,
@SenderId bigint
AS
BEGIN
SET NOCOUNT ON;

[Code] .....

The problem with this is I'm trying to connect to the user photos table to return their profile picture, but for some reason even though I have specified IsProfilePic I get all the photos returned, instead it should be two photos, one for the @UserId and the other for the @SenderId, its equivalent to me doing this:

Select *
From [User].[User_Photos]
where (UserId = 1 or UserId = 2) and IsProfilePic = 1

And this returns me the correct information.