How to convert image to smaller image array

So I need to create a program that converts an image/scene into smiley faces. The basic idea is this; I will have a scene with an image in it, and I want to create a shader or script that can turn that image into an array of :) faces. Similar to this, except instead of hexagons it would be :)

I managed to create a simple shader that turns an image into a mosiac, but I don't know I how I would turn it to smileys from there. The mosiac code

 Shader "STYLY/Examples/Mosaic" {
     Properties{
         _MainTex("Texture", 2D) = "white" {}
         [Space]
         _Color("Main Color", Color) = (1,1,1,1)
         [HDR]_EmissionColor("Emission Color", Color) = (0,0,0,1)
         _MosaicResolution("Mosaic Resolution", Range(2, 128)) = 32
         _MosaicResolutionX("X Mosaic Resolution", Range(1, 4)) = 1
         _MosaicResolutionY("Y Mosaic Resolution", Range(1, 4)) = 1
 
         [Space]
         _Glossiness("Smoothness", Range(0,1)) = 0
         _Metallic("Metallic", Range(0,1)) = 0
     }
         SubShader{
             Tags { "RenderType" = "Opaque" }
             LOD 200
 
             CGPROGRAM
             #pragma surface surf Standard fullforwardshadows
             #pragma target 3.0
 
             sampler2D _MainTex;
 
             struct Input {
                 float2 uv_MainTex;
             };
 
             half4 _Color;
             half4 _EmissionColor;
 
             half _Glossiness;
             half _Metallic;
             int _MosaicResolution;
             int _MosaicResolutionX;
             int _MosaicResolutionY;
 
     #define MOSAIC (_MosaicResolution * float2(_MosaicResolutionX, _MosaicResolutionY))
 
             // Surface Shader
             void surf(Input IN, inout SurfaceOutputStandard o) {
                 float2 uv = IN.uv_MainTex;
                 uv = floor(uv * MOSAIC) / MOSAIC;
 
                 fixed4 c = tex2D(_MainTex, uv);
                 o.Albedo = c.rgb * _Color;
                 o.Emission = c.rgb * _EmissionColor;
                 o.Metallic = _Metallic;
                 o.Smoothness = _Glossiness;
                 o.Alpha = 1.0;
             }
             ENDCG
         }
             FallBack "Diffuse"
 }

So my question is, how would I, instead of making the images squares, make them in the shape of :) ?