diff --git a/addons/web_editor/models/ir_attachment.py b/addons/web_editor/models/ir_attachment.py
index dfc95e361cc..b9a1986727a 100644
--- a/addons/web_editor/models/ir_attachment.py
+++ b/addons/web_editor/models/ir_attachment.py
@@ -14,7 +14,7 @@ class IrAttachment(models.Model):
     image_src = fields.Char(compute='_compute_image_src')
     image_width = fields.Integer(compute='_compute_image_size')
     image_height = fields.Integer(compute='_compute_image_size')
-    original_id = fields.Many2one('ir.attachment', string="Original (unoptimized, unresized) attachment")
+    original_id = fields.Many2one('ir.attachment', string="Original (unoptimized, unresized) attachment", index=True)
 
     def _compute_local_url(self):
         for attachment in self: