Fix All Memory Leaks

[SkyeHoefling]

Description

After implementing automated benchmarking it documented there are large memory leaks with the current implementation. The data is available in #20 as well as the table copied below

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BenchmarkDotNet=v0.13.0, OS=Windows 10.0.17763.2114 (1809/October2018Update/Redstone5)
Intel Xeon Platinum 8171M CPU 2.60GHz, 1 CPU, 2 logical and 2 physical cores
.NET SDK=5.0.400
 [Host]     : .NET 5.0.9 (5.0.921.35908), X64 RyuJIT
 Job-VLDWLB : .NET 5.0.9 (5.0.921.35908), X64 RyuJIT

Runtime=.NET 5.0  InvocationCount=1  LaunchCount=1  
UnrollFactor=1  

Method	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated	Allocated native memory	Native memory leak
Thumbnail_Write	60.91 ms	1.208 ms	2.269 ms	-	-	-	112 B	4,937,059 B	295,469 B

primary

BenchmarkDotNet=v0.13.0, OS=Windows 10.0.17763.2114 (1809/October2018Update/Redstone5)
Intel Xeon Platinum 8171M CPU 2.60GHz, 1 CPU, 2 logical and 2 physical cores
.NET SDK=5.0.400
 [Host]     : .NET 5.0.9 (5.0.921.35908), X64 RyuJIT
 Job-DXULZI : .NET 5.0.9 (5.0.921.35908), X64 RyuJIT

Runtime=.NET 5.0  InvocationCount=1  LaunchCount=1  
UnrollFactor=1  

Method	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated	Allocated native memory	Native memory leak
PrimaryImage_Write	2.947 s	0.0303 s	0.0268 s	-	-	-	128 B	210,038,978 B	18,048,557 B

We need to ensure all native memory is freed so these result in 0 native memory leaked