Pulse graham crackers and pecans in a food processor until finely ground.
Pour into a large bowl and add melted butter and 1/4 cup sugar. Stir to mix.
Press into a 9x13-inch pan and bake at 350 degrees for 8 minutes. Let cool.
Using an electric mixer, beat cream cheese, milk, and confectioners' sugar until smooth. Fold in 1 cup of whipped topping. (Save remaining whipped topping for the final layer.)
Spread cream cheese mixture on top of crust.
Spread blueberry pie filling on top of cream cheese layer.
Top with remaining whipped topping.
Chill thoroughly before serving.