How to display the image and text in WPF TreeGrid (SfTreeGrid) column ?
WPF TreeGrid (SfTreeGrid) allows you to display image and text in the columns by using TreeGridTemplateColumn.
<syncfusion:TreeGridTemplateColumn MappingName="FirstName">
<syncfusion:TreeGridTemplateColumn.CellTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="Employee.png" HorizontalAlignment="Left" Margin="5" VerticalAlignment="Center"/>
<TextBlock Text="{Binding FirstName}"/>
</StackPanel>
</DataTemplate>
</syncfusion:TreeGridTemplateColumn.CellTemplate>
<syncfusion:TreeGridTemplateColumn.EditTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="Employee.png" HorizontalAlignment="Left" Margin="5" VerticalAlignment="Center"/>
<TextBox Text="{Binding FirstName, Mode=TwoWay}"/>
</StackPanel>
</DataTemplate>
</syncfusion:TreeGridTemplateColumn.EditTemplate>
</syncfusion:TreeGridTemplateColumn>

Take a moment to peruse the documentation, where you can find about template column support in SfTreeGrid, with code examples.