Index: /trunk/src/org/openstreetmap/josm/gui/layer/geoimage/ImageEntry.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/layer/geoimage/ImageEntry.java	(revision 17579)
+++ /trunk/src/org/openstreetmap/josm/gui/layer/geoimage/ImageEntry.java	(revision 17580)
@@ -106,5 +106,5 @@
     @Override
     public int hashCode() {
-        return Objects.hash(super.hashCode(), thumbnail);
+        return Objects.hash(super.hashCode(), thumbnail, dataSet);
     }
 
Index: /trunk/test/unit/org/openstreetmap/josm/gui/layer/geoimage/ImageEntryTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/layer/geoimage/ImageEntryTest.java	(revision 17579)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/layer/geoimage/ImageEntryTest.java	(revision 17580)
@@ -5,7 +5,9 @@
 
 import java.io.File;
+import java.util.ArrayList;
 
 import org.junit.jupiter.api.Test;
 import org.openstreetmap.josm.TestUtils;
+import org.openstreetmap.josm.data.ImageData;
 import org.openstreetmap.josm.data.gpx.GpxImageEntry;
 
@@ -37,4 +39,5 @@
             .suppress(Warning.NONFINAL_FIELDS)
             .withPrefabValues(GpxImageEntry.class, new GpxImageEntry(new File("foo")), new GpxImageEntry(new File("bar")))
+            .withPrefabValues(ImageData.class, new ImageData(), new ImageData(new ArrayList<>()))
             .verify();
     }