use GUID for image name

tests/lib/lib_linux.ps1

@@ -1,15 +1,17 @@
 function WSL-Install() {
+    $id = [guid]::NewGuid().ToString()
+
     # Build docker image from the provided tarball
     $tmpdir = $(mktemp -d)
     Copy-Item $PSScriptRoot/Dockerfile $tmpdir
     Copy-Item nixos-wsl-installer.tar.gz $tmpdir
-    docker build -t local:nixos-wsl $tmpdir | Write-Host
+    docker build -t nixos-wsl:$id $tmpdir | Write-Host
     Remove-Item $tmpdir -Recurse -Force
 
     # Spawn a new docker container
-    $id = docker run -di --privileged --init local:nixos-wsl /bin/sh
+    docker run -di --privileged --init --name $id nixos-wsl:$id /bin/sh
     if ($LASTEXITCODE -ne 0) {
-        throw "Failed to launch docker container"
+        throw "Failed to launch container"
     }
 
     return $id
@@ -22,6 +24,10 @@ function WSL-Launch([string]$id, [string]$command) {
 function WSL-Uninstall([string]$id) {
     docker rm -f $id
     if ($LASTEXITCODE -ne 0) {
-        throw "Failed to remove docker container"
+        throw "Failed to remove container"
+    }
+    docker rmi nixos-wsl:$id
+    if ($LASTEXITCODE -ne 0) {
+        throw "Failed to remove image"
     }
 }