ChangePropertyAction on Image Control in LongListSelector item template - image

Question

I have a long list selector and i have a datatemplate as item template, containing an image. I want the source to change based on a property from the model. I tried with a converter but i could't get it to work.
Now i'm trying with triggers. I have:
<Image Name="MovieThumbnail">
<i:Interaction.Triggers>
<ei:DataTrigger Binding="{Binding DataContext.IsCategoryCurrent,ElementName=LayoutRoot}" Value="true">
<ei:ChangePropertyAction TargetObject="{Binding ElementName=MovieThumbnail}" TargetName="Source" Value="{Binding Path=Image120x170}" PropertyName="Source"/>
</ei:DataTrigger>
<ei:DataTrigger Binding="{Binding DataContext.IsCategoryCurrent,ElementName=LayoutRoot}" Value="false">
<ei:ChangePropertyAction TargetObject="{Binding ElementName=MovieThumbnail}" TargetName="Source" Value="{x:Null}" PropertyName="Source"/>
</ei:DataTrigger>
</i:Interaction.Triggers>
</Image>
It work almost how i want it to, except that images repeat themselves. As in a movie has the picture of another movie. I think it's because i bind by element name and the image control has multiple instances (one for each item), but i would think they can't see each other. Any help highly appreciated.
EDIT:
After further investigation, it seems that this happens because of the long list selector.
I first load 40 items, and then load another 40, but the second batch of 40 items get the pictures from the first batch. If i raise a property changed event, then the pictures from the second batch are set on all items repeating themselves. I have no idea why this is happening.
If i load another 40 and raise property changed on IsCategoryCurrent again, the pictures from the 3rd batch get set 3 times.

Answer 1

I managed to fix it:
<Image
Grid.RowSpan="2"
Name="MovieThumbnail"
Stretch="Fill"
Width="130" Height="195"
HorizontalAlignment="Center"
VerticalAlignment="Center">
<i:Interaction.Triggers>
<ei:DataTrigger Binding="{Binding DataContext.IsCategoryCurrent,ElementName=LayoutRoot}"
Value="true">
<ei:ChangePropertyAction TargetObject="{Binding ElementName=MovieThumbnail}"
TargetName="Source"
PropertyName="Source">
<ei:ChangePropertyAction.Value>
<BitmapImage CreateOptions="BackgroundCreation"
UriSource="{Binding Path=Image120x170}"/>
</ei:ChangePropertyAction.Value>
</ei:ChangePropertyAction>
</ei:DataTrigger>
<ei:DataTrigger Binding="{Binding DataContext.IsCategoryCurrent,ElementName=LayoutRoot}"
Value="false">
<ei:ChangePropertyAction TargetObject="{Binding ElementName=MovieThumbnail}"
TargetName="Source"
Value="{x:Null}"
PropertyName="Source"/>
</ei:DataTrigger>
</i:Interaction.Triggers>
</Image>
And i raise a property changed event of IsCategoryCurrent at every change.