diff --git a/changes/3125.fix.md b/changes/3125.fix.md
new file mode 100644
index 00000000000..aca040cad64
--- /dev/null
+++ b/changes/3125.fix.md
@@ -0,0 +1 @@
+Fix outdated image string join logic in `ImageRow.image_ref`.
diff --git a/src/ai/backend/common/utils.py b/src/ai/backend/common/utils.py
index 5d98b54d337..4eed2a03668 100644
--- a/src/ai/backend/common/utils.py
+++ b/src/ai/backend/common/utils.py
@@ -419,7 +419,7 @@ def is_ip_address_format(str: str) -> bool:
         return False
 
 
-def join_non_empty(*args, sep):
+def join_non_empty(*args: Optional[str], sep: str) -> str:
     """
     Joins non-empty strings from the given arguments using the specified separator.
     """
diff --git a/src/ai/backend/manager/models/image.py b/src/ai/backend/manager/models/image.py
index d4724f7db76..b946f334c0f 100644
--- a/src/ai/backend/manager/models/image.py
+++ b/src/ai/backend/manager/models/image.py
@@ -35,6 +35,7 @@
     ImageRegistry,
     ResourceSlot,
 )
+from ai.backend.common.utils import join_non_empty
 from ai.backend.logging import BraceStyleAdapter
 from ai.backend.manager.models.container_registry import ContainerRegistryRow
 
@@ -264,7 +265,8 @@ def image_ref(self) -> ImageRef:
             image_name = ""
             _, tag = ImageRef.parse_image_tag(self.name.split(f"{self.registry}/", maxsplit=1)[1])
         else:
-            image_and_tag = self.name.split(f"{self.registry}/{self.project}/", maxsplit=1)[1]
+            join = functools.partial(join_non_empty, sep="/")
+            image_and_tag = self.name.removeprefix(f"{join(self.registry, self.project)}/")
             image_name, tag = ImageRef.parse_image_tag(image_and_tag)
 
         return ImageRef(