diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index d5e88ce..32aa009 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -1737,16 +1737,21 @@ let setreplacedictentry s =
 let setprintdictentry s =
   setop (PrintDictEntry s) ()
 
+let pdf_or_json s =
+  match explode s with
+  | 'P'::'D'::'F'::r -> Pdfread.parse_single_object (implode r)
+  | _ -> Cpdfjson.object_of_json (Cpdfyojson.Safe.from_string s)
+
 let setreplacedictentryvalue s =
   try
-    let pdfobj = Cpdfjson.object_of_json (Cpdfyojson.Safe.from_string s) in
+    let pdfobj = pdf_or_json s in
       args.replace_dict_entry_value <- pdfobj
   with
     e -> error (Printf.sprintf "Failed to parse replacement value: %s\n" (Printexc.to_string e))
 
 let setdictentrysearch s =
   try
-    let pdfobj = Cpdfjson.object_of_json (Cpdfyojson.Safe.from_string s) in
+    let pdfobj = pdf_or_json s in
       args.dict_entry_search <- Some pdfobj
   with
     e -> error (Printf.sprintf "Failed to parse search term: %s\n" (Printexc.to_string e))
@@ -1966,7 +1971,7 @@ let setreadableops () =
 let addeltinfo s =
   match String.split_on_char '=' s with
   | h::t ->
-      let pdfobj = Pdfread.parse_single_object (String.concat "" t) in
+      let pdfobj = pdf_or_json (String.concat "" t) in
         Cpdfdrawcontrol.eltinfo h pdfobj
   | [] -> error "addeltinfo: bad format"
 
@@ -4684,7 +4689,7 @@ let go () =
         print_obj args.format_json pdf s
   | Some (ReplaceObj (a, b)) ->
       let pdf = get_single_pdf args.op false in
-      let pdfobj = Cpdfjson.object_of_json (Cpdfyojson.Safe.from_string b) in
+      let pdfobj = pdf_or_json b in
         replace_obj pdf a pdfobj;
         write_pdf false pdf
   | Some (Verify standard) ->
diff --git a/cpdfmanual.pdf b/cpdfmanual.pdf
index 314eb5d..edd35f9 100644
Binary files a/cpdfmanual.pdf and b/cpdfmanual.pdf differ
diff --git a/cpdfmanual.tex b/cpdfmanual.tex
index 90b7da5..0e7cce7 100644
--- a/cpdfmanual.tex
+++ b/cpdfmanual.tex
@@ -5373,7 +5373,7 @@ By default, Cpdf with \texttt{-draw-struct-tree} will mark anything not automati
 
 Some tags require a namespace other than the default. You can set the namespace with \texttt{-namespace}, which affects all future tags until reset. Two namespace abbreviations are available: \texttt{PDF} for the default \texttt{http://iso.org/pdf/ssn} namespace and \texttt{PDF2} for the PDF 2.0 namespace \texttt{http://iso.org/pdf2/ssn}.
 
-Extra information may be added to structure tree nodes with \texttt{-eltinfo} / \texttt{-end-eltinfo}. For example, to set the alternative description for an image, we might write \texttt{-eltinfo "Alt=A large horse" -image A -end-eltinfo}. Multiple items may be set at once, for example Alt, ActualText, Lang etc. 
+Extra information may be added to structure tree nodes with \texttt{-eltinfo} / \texttt{-end-eltinfo}. For example, to set the alternative description for an image, we might write (in JSON format, or prefixing with \texttt{PDF} in PDF format) \texttt{-eltinfo "Alt=PDF(A large horse)" -image A -end-eltinfo}. Multiple items may be set at once, for example Alt, ActualText, Lang etc. 
 
 A role map, which maps non-standard structure types to standard ones, may be set with \texttt{-rolemap}. For example \texttt{-rolemap "/S1/H1/S2/H2"} would map the S1 structure type to the standard type H1 and so on.