diff --git a/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb b/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
index bc145cd0..ae3d9c71 100644
--- a/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
+++ b/ruby/lib/asciidoctor/extensions/asciidoctor_kroki/extension.rb
@@ -272,7 +272,7 @@ class KrokiDiagram
 
     attr_reader :type, :text, :format, :target
 
-    def initialize(type, format, text, target)
+    def initialize(type, format, text, target = nil)
       @text = text
       @type = type
       @format = format
diff --git a/ruby/spec/asciidoctor_kroki_diagram_spec.rb b/ruby/spec/asciidoctor_kroki_diagram_spec.rb
index f4a88275..13321d47 100644
--- a/ruby/spec/asciidoctor_kroki_diagram_spec.rb
+++ b/ruby/spec/asciidoctor_kroki_diagram_spec.rb
@@ -32,7 +32,28 @@
     output_dir_path = "#{__dir__}/../.asciidoctor/kroki"
     diagram_name = kroki_diagram.save(output_dir_path, kroki_client)
     diagram_path = File.join(output_dir_path, diagram_name)
-    expect(File.exist?(diagram_path)).to be_truthy, "expected diagram to be saved at #{diagram_path}"
+    expect(File.exist?(diagram_path)).to be_truthy, "diagram should be saved at: #{diagram_path}"
+    content = <<-TXT.chomp
+     ,-----.          ,---.
+     |alice|          |bob|
+     `--+--'          `-+-'
+        |    hello      |
+        |-------------->|
+     ,--+--.          ,-+-.
+     |alice|          |bob|
+     `-----'          `---'
+    TXT
+    expect(File.read(diagram_path).split("\n").map(&:rstrip).join("\n")).to eq(content)
+  end
+  it 'should fetch a diagram from Kroki and save it to disk using the target name' do
+    kroki_diagram = ::AsciidoctorExtensions::KrokiDiagram.new('plantuml', 'txt', ' alice -> bob: hello', 'hello-world')
+    kroki_http_client = ::AsciidoctorExtensions::KrokiHttpClient
+    kroki_client = ::AsciidoctorExtensions::KrokiClient.new(server_url: 'https://kroki.io', http_method: 'get', http_client: kroki_http_client)
+    output_dir_path = "#{__dir__}/../.asciidoctor/kroki"
+    diagram_name = kroki_diagram.save(output_dir_path, kroki_client)
+    diagram_path = File.join(output_dir_path, diagram_name)
+    expect(diagram_name).to start_with('hello-world-'), "diagram name should use the target as a prefix, got: #{diagram_name}"
+    expect(File.exist?(diagram_path)).to be_truthy, "diagram should be saved at: #{diagram_path}"
     content = <<-TXT.chomp
      ,-----.          ,---.
      |alice|          |bob|
@@ -55,9 +76,9 @@
     expect(kroki_http_client).to receive(:get).once.and_return(diagram_contents)
     diagram_name = kroki_diagram.save(output_dir_path, kroki_client)
     diagram_path = File.join(output_dir_path, diagram_name)
-    expect(File.exist?(diagram_path)).to be_truthy, "expected diagram to be saved at #{diagram_path}"
+    expect(File.exist?(diagram_path)).to be_truthy, "diagram should be saved at: #{diagram_path}"
     # calling again... should read the file from disk (and not do a GET request)
     kroki_diagram.save(output_dir_path, kroki_client)
-    expect(File.size(diagram_path)).to be_eql(diagram_contents.length), 'expected diagram to be fully saved on disk'
+    expect(File.size(diagram_path)).to be_eql(diagram_contents.length), 'diagram should be fully saved on disk'
   end
 end
diff --git a/test/antora/test.spec.js b/test/antora/test.spec.js
index 463c5bd4..1827f87f 100644
--- a/test/antora/test.spec.js
+++ b/test/antora/test.spec.js
@@ -20,7 +20,7 @@ describe('Antora integration', () => {
     expect(imageElements.length).to.equal(6)
     imageElements.each((i, imageElement) => {
       const src = $(imageElement).attr('src')
-      expect(src).to.startWith('_images/diag-')
+      expect(src).to.startWith('_images/ab-')
     })
   }).timeout(50000)
 })
diff --git a/test/test.spec.js b/test/test.spec.js
index 617f1449..80cd2deb 100644
--- a/test/test.spec.js
+++ b/test/test.spec.js
@@ -240,7 +240,7 @@ Hello -> World
         extension_registry: registry,
         attributes: { 'kroki-fetch-diagram': true }
       })
-      expect(html).to.contain('<img src=".asciidoctor/kroki/diag-7a123c0b2909750ca5526554cd8620774ccf6cd9.svg" alt="hello-world">')
+      expect(html).to.contain('<img src=".asciidoctor/kroki/hello-world-7a123c0b2909750ca5526554cd8620774ccf6cd9.svg" alt="hello-world">')
     }).timeout(5000)
     it('should download and save an image to a local folder and generated name', () => {
       const input = `