diff --git a/AzureSearchEmulator.Aspire.DemoAppHost/AppHost.cs b/AzureSearchEmulator.Aspire.DemoAppHost/AppHost.cs
index 6616435..c8bc1d0 100644
--- a/AzureSearchEmulator.Aspire.DemoAppHost/AppHost.cs
+++ b/AzureSearchEmulator.Aspire.DemoAppHost/AppHost.cs
@@ -6,6 +6,11 @@
 
 // Example container usage via F23.Aspire.Hosting.AzureSearchEmulator
 builder.AddAzureSearchEmulator("emulator-container")
+    // The package pins the image tag to its own version, but that image is not published until the
+    // release is tagged -- so in this repo the pinned tag does not exist yet and the pull fails.
+    // The demo tracks the code in the working tree rather than a release, so "latest" is the right
+    // tag here. Consumers of the package should leave the pinned default alone.
+    .WithImageTag("latest")
     .WithIndexesVolume();
 
 builder.Build().Run();
diff --git a/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceExtensionsTests.cs b/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceExtensionsTests.cs
index 06d4942..ef4e451 100644
--- a/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceExtensionsTests.cs
+++ b/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceExtensionsTests.cs
@@ -106,6 +106,30 @@ await callback.Callback(new HttpsCertificateConfigurationCallbackAnnotationConte
         return await valueProvider.GetValueAsync(TestContext.Current.CancellationToken);
     }
 
+    [Fact]
+    public void AddAzureSearchEmulator_PinsImageTagToPackageVersion()
+    {
+        // "latest" is an ordinary Docker tag, so a host that had already pulled it kept running the
+        // image from that first pull and never picked up the emulator a newer package expects.
+        // Pinning to the package version means upgrading the NuGet reference pulls a tag the host
+        // does not have yet.
+
+        // Arrange
+        var builder = DistributedApplication.CreateBuilder();
+
+        // Act
+        var resource = builder.AddAzureSearchEmulator("my-emulator").Resource;
+
+        // Assert
+        Assert.True(resource.TryGetAnnotationsOfType<ContainerImageAnnotation>(out var imageAnnotations));
+        var image = Assert.Single(imageAnnotations);
+
+        Assert.Equal("ghcr.io", image.Registry);
+        Assert.Equal("feature23/azuresearchemulator", image.Image);
+        Assert.Equal(AzureSearchEmulatorResource.ImageTag, image.Tag);
+        Assert.NotEqual("latest", image.Tag);
+    }
+
     [InlineData(false)]
     [InlineData(true)]
     [Theory]
diff --git a/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceTests.cs b/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceTests.cs
index d9bf234..09a936e 100644
--- a/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceTests.cs
+++ b/AzureSearchEmulator.Aspire.Tests/AzureSearchEmulatorResourceTests.cs
@@ -1,4 +1,5 @@
-using F23.Aspire.Hosting.AzureSearchEmulator;
+using System.Xml.Linq;
+using F23.Aspire.Hosting.AzureSearchEmulator;
 
 namespace AzureSearchEmulator.Aspire.Tests;
 
@@ -16,4 +17,51 @@ public void Constructor_InitializesResourceProperly()
         // Assert
         Assert.Equal(name, resource.Name);
     }
+
+    [Fact]
+    public void ImageTag_MatchesPackageVersion()
+    {
+        // The emulator image and this package are released together, so the pinned tag has to be a
+        // tag the release actually publishes. The Docker workflow tags images from the git tag via
+        // `type=semver,pattern={{version}}`, so `v1.2.3` publishes the image tag `1.2.3` -- which
+        // is the package version. Deriving the tag from the assembly keeps the two in step without
+        // a second place to edit at release time; this asserts that derivation stays correct.
+
+        // Arrange
+        // Read the version the package actually ships from the csproj, rather than from the
+        // assembly the tag is already derived from -- comparing the derivation against its own
+        // input would pass no matter what the release version is.
+        var csproj = Path.Combine(GetRepositoryRoot(),
+            "AzureSearchEmulator.Aspire", "AzureSearchEmulator.Aspire.csproj");
+
+        var packageVersion = XDocument.Load(csproj)
+            .Descendants("Version")
+            .Single()
+            .Value
+            .Trim();
+
+        // Act
+        var tag = AzureSearchEmulatorResource.ImageTag;
+
+        // Assert
+        Assert.Equal(packageVersion, tag);
+
+        // The SDK appends "+<commit sha>" to the informational version, which is not part of any
+        // published image tag.
+        Assert.DoesNotContain('+', tag);
+    }
+
+    private static string GetRepositoryRoot()
+    {
+        var directory = new DirectoryInfo(AppContext.BaseDirectory);
+
+        while (directory is not null && !File.Exists(Path.Combine(directory.FullName, "AzureSearchEmulator.sln")))
+        {
+            directory = directory.Parent;
+        }
+
+        Assert.NotNull(directory);
+
+        return directory.FullName;
+    }
 }
diff --git a/AzureSearchEmulator.Aspire/AzureSearchEmulator.Aspire.csproj b/AzureSearchEmulator.Aspire/AzureSearchEmulator.Aspire.csproj
index 7f3c6c3..4abdfb9 100644
--- a/AzureSearchEmulator.Aspire/AzureSearchEmulator.Aspire.csproj
+++ b/AzureSearchEmulator.Aspire/AzureSearchEmulator.Aspire.csproj
@@ -13,7 +13,7 @@
         <PackageTags>azure search emulator ai hosting docker</PackageTags>
         <Description>Azure Search Emulator hosting support for Aspire.</Description>
         <IsPackable>true</IsPackable>
-        <Version>1.0.0-beta.3</Version>
+        <Version>1.0.0-beta.4</Version>
         <Company>feature[23]</Company>
         <Copyright>Copyright (c) feature[23] 2025</Copyright>
         <Authors>Paul Irwin</Authors>
diff --git a/AzureSearchEmulator.Aspire/AzureSearchEmulatorResource.cs b/AzureSearchEmulator.Aspire/AzureSearchEmulatorResource.cs
index 438fe7c..5e1b19e 100644
--- a/AzureSearchEmulator.Aspire/AzureSearchEmulatorResource.cs
+++ b/AzureSearchEmulator.Aspire/AzureSearchEmulatorResource.cs
@@ -1,4 +1,5 @@
-using Aspire.Hosting.ApplicationModel;
+using System.Reflection;
+using Aspire.Hosting.ApplicationModel;
 
 namespace F23.Aspire.Hosting.AzureSearchEmulator;
 
@@ -6,4 +7,27 @@ public class AzureSearchEmulatorResource(string name) : ContainerResource(name)
 {
     public const int DefaultHttpPort = 5100;
     public const int DefaultHttpsPort = 5143;
+
+    internal const string ImageRegistry = "ghcr.io";
+    internal const string ImageName = "feature23/azuresearchemulator";
+
+    /// <summary>
+    /// The container image tag used by <see cref="AzureSearchEmulatorResourceExtensions"/>.
+    /// </summary>
+    /// <remarks>
+    /// This is the emulator version that matches this package's version, rather than "latest".
+    /// Docker treats "latest" as an ordinary tag, so a host that had already pulled it kept running
+    /// the image it pulled the first time and never picked up the emulator that a newer package
+    /// expects. Pinning ties the container to the package, so upgrading the NuGet reference pulls
+    /// the matching image.
+    ///
+    /// This is asserted against the package version by AzureSearchEmulatorResourceTests, so
+    /// releasing a new version does not need this value updated by hand.
+    /// </remarks>
+    internal static readonly string ImageTag = typeof(AzureSearchEmulatorResource).Assembly
+        .GetCustomAttribute<AssemblyInformationalVersionAttribute>()!
+        .InformationalVersion
+        // The SDK appends "+<commit sha>" to the informational version; the published image tag
+        // carries only the version itself.
+        .Split('+')[0];
 }
diff --git a/AzureSearchEmulator.Aspire/AzureSearchEmulatorResourceExtensions.cs b/AzureSearchEmulator.Aspire/AzureSearchEmulatorResourceExtensions.cs
index bbd724c..90672a3 100644
--- a/AzureSearchEmulator.Aspire/AzureSearchEmulatorResourceExtensions.cs
+++ b/AzureSearchEmulator.Aspire/AzureSearchEmulatorResourceExtensions.cs
@@ -21,7 +21,8 @@ public static class AzureSearchEmulatorResourceExtensions
         /// <remarks>
         /// It is recommended to configure a volume for persisting index data using
         /// <see cref="WithIndexesVolume"/>.
-        /// You can also override the default image tag ("latest") by using the returned resource builder's
+        /// The image tag defaults to the emulator version matching this package's version. You can
+        /// override it by using the returned resource builder's
         /// <see cref="ContainerResourceBuilderExtensions.WithImageTag{T}"/> method.
         /// </remarks>
         public IResourceBuilder<AzureSearchEmulatorResource> AddAzureSearchEmulator(string name,
@@ -32,9 +33,9 @@ public IResourceBuilder<AzureSearchEmulatorResource> AddAzureSearchEmulator(stri
 
 #pragma warning disable ASPIRECERTIFICATES001 // WithHttpsDeveloperCertificate is experimental; see comment below.
             var resourceBuilder = builder.AddResource(resource)
-                .WithImage("feature23/azuresearchemulator")
-                .WithImageTag("latest")
-                .WithImageRegistry("ghcr.io")
+                .WithImage(AzureSearchEmulatorResource.ImageName)
+                .WithImageTag(AzureSearchEmulatorResource.ImageTag)
+                .WithImageRegistry(AzureSearchEmulatorResource.ImageRegistry)
                 .WithHttpEndpoint(port: httpPort, targetPort: AzureSearchEmulatorResource.DefaultHttpPort, env: "HTTP_PORTS")
                 .WithHttpsEndpoint(port: httpsPort, targetPort: AzureSearchEmulatorResource.DefaultHttpsPort, env: "HTTPS_PORTS")
                 .WithEnvironment("ASPNETCORE_URLS", $"https://+:{resource.GetEndpoint("https").Property(EndpointProperty.Port)};http://+:{resource.GetEndpoint("http").Property(EndpointProperty.Port)}")
diff --git a/AzureSearchEmulator/AzureSearchEmulator.csproj b/AzureSearchEmulator/AzureSearchEmulator.csproj
index 4d91153..5172aba 100644
--- a/AzureSearchEmulator/AzureSearchEmulator.csproj
+++ b/AzureSearchEmulator/AzureSearchEmulator.csproj
@@ -5,7 +5,7 @@
 		<UserSecretsId>6751dc28-24d4-4572-8f44-e652593dd678</UserSecretsId>
 		<Nullable>enable</Nullable>
 		<ImplicitUsings>enable</ImplicitUsings>
-		<Version>1.0.0-beta.3</Version>
+		<Version>1.0.0-beta.4</Version>
 		<WarningsAsErrors>Nullable</WarningsAsErrors>
 		<LangVersion>14</LangVersion>
 		<IsPackable>true</IsPackable>