Replace screenshots with DX12U versions

Author: sebmerry

README.md

@@ -10,15 +10,15 @@ In the Samples directory, you will find samples that attempt to break off specif
 ### DirectX 12 Ultimate samples
 1. [D3D12 Mesh Shaders](Samples/Desktop/D3D12MeshShaders/readme.md): This sample demonstrates how Mesh shaders can be used to increase the flexibility and performance of the geometry pipeline.
 
-    <img src="Assets/DirectX12Ultimate_small.png" alt="DirectX 12 Ultimate" height="200"><img src="Samples/Desktop/D3D12MeshShaders/src/MeshletRender/D3D12MeshletRender.png" alt="D3D12 Meshlet Render preview" height="200"> 
+    <img src="Samples/Desktop/D3D12MeshShaders/src/MeshletRender/Screenshot_DX12U.png" alt="D3D12 Meshlet Render preview" height="200">
 
 1. [D3D12 Variable Rate Shading](Samples/Desktop/D3D12VariableRateShading/readme.md): This sample demonstrates how shading rate can be reduced with little or no reduction in visual quality, leading to “free” performance.
 
-    <img src="Assets/DirectX12Ultimate_small.png" alt="DirectX 12 Ultimate" height="200"><img src="Samples/Desktop/D3D12VariableRateShading/src/Screenshot_small.png" alt="D3D12 Variable Rate Shading GUI" height="200"> 
+    <img src="Samples/Desktop/D3D12VariableRateShading/src/Screenshot_DX12U.png" alt="D3D12 Variable Rate Shading GUI" height="200">
 
 1. [D3D12 Raytracing](Samples/Desktop/D3D12Raytracing/readme.md): This sample demonstrates how DirectX Raytracing (DXR) brings a new level of graphics realism to video games, previously only achievable in the movie industry.
 
-    <img src="Assets/DirectX12Ultimate_small.png" alt="DirectX 12 Ultimate" height="200"><img src="Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/Screenshot_small.png" alt="D3D12 Raytracing Real-Time Denoised Ambient Occlusion preview" height="200">
+    <img src="Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/Screenshot_DX12U.png" alt="D3D12 Raytracing Real-Time Denoised Ambient Occlusion preview" height="200">
 
 ## MiniEngine: A DirectX 12 Engine Starter Kit
 In addition to the samples, we are announcing the first DirectX 12 preview release of the MiniEngine.