fix: a size change labels its images like every other failure

CHANGELOG.md

@@ -413,6 +413,9 @@ One removal 2.0 cannot warn about, written down instead: the legacy `LOADED_DRIV
   `skip_stack_frames: 1` (see docs/configuration.md)
 - **RSpec prints a failed screenshot once.** The adapter re-raised it inside a `rescue`,
   so RSpec repeated the whole failure under `Caused by:`
+- **A size change labels its images like every other failure.** `Dimensions have
+  changed` now lists `baseline:` and `actual:`, relative to the project root, instead of
+  two bare absolute paths, and never names annotations left over from an earlier run
 
 ### Known limitations
 - **One process per worker** (`parallel_tests`, RSpec, CI sharding) still writes one

lib/snap_diff/reporters/default.rb

@@ -51,8 +51,10 @@ def annotate_and_save_images
         annotation_service.annotate_and_save_images
       end
 
+      # Images of different sizes are never annotated, so only the two inputs
+      # are listed: annotations on disk are leftovers from an earlier failure.
       def build_error_for_different_dimensions
-        "Dimensions have changed: #{dimension_change}\n#{base_image_path.to_path}\n#{image_path.to_path}"
+        ["Dimensions have changed: #{dimension_change}", *artifact_lines(INPUT_ARTIFACTS)].join(NEW_LINE)
       end
 
       # "WxH => WxH", baseline first. Public so Reporters::HTML says it the
@@ -93,6 +95,8 @@ def self.percent(fraction)
         "heatmap" => :heatmap_diff_path
       }.freeze
 
+      INPUT_ARTIFACTS = ARTIFACT_LABELS.slice("baseline", "actual").freeze
+
       def build_error_message
         [headline, *metric_lines, *artifact_lines].join(NEW_LINE)
       end
@@ -138,8 +142,8 @@ def thresholds
       # Only what is on disk gets a line: the heatmap exists solely for
       # drivers that produce a diff mask, and a comparison can be reported
       # before either input has been written out.
-      def artifact_lines
-        present = ARTIFACT_LABELS.filter_map do |label, path_method|
+      def artifact_lines(labels = ARTIFACT_LABELS)
+        present = labels.filter_map do |label, path_method|
           path = send(path_method)
           [label, path] if path.exist?
         end

test/unit/reporters/default_test.rb

@@ -161,6 +161,24 @@ class DefaultReporterTest < ActiveSupport::TestCase
     end
   end
 
+  # A size change draws no annotations, so its message lists only the two
+  # inputs, even when an earlier same-size failure left annotations on disk.
+  test "a size change labels its two inputs like any other failure" do
+    base = @_tmpdir / "header.base.png"
+    new = @_tmpdir / "header.png"
+    FileUtils.cp(TEST_IMAGES_DIR / "a.png", base)
+    FileUtils.cp(TEST_IMAGES_DIR / "a_cropped.png", new)
+    %w[header.diff.png header.base.diff.png header.heatmap.diff.png].each { |stale| FileUtils.touch(@_tmpdir / stale) }
+
+    with_config_root(@_tmpdir) do
+      assert_equal <<~MESSAGE.chomp, SnapDiff::Comparison.new(new, base).processed.error_message
+        Dimensions have changed: 80x80 => 80x60
+          baseline: header.base.png
+          actual:   header.png
+      MESSAGE
+    end
+  end
+
   private
 
   def with_config_root(root)