.ssp digest: add image file's own pixel dimensions

Complete image file digest identity record: add
px:<width>x<height> to the .ssp image record, read from the
image file header (imageformats.read_image_info, no decode):

  .image: won_benkler_2_1.png sha256:5BA4...D128 bytes:93861 px:420x342

(The w##h## dimensions in the markup are display dimensions, not the
file's: they are author set, or where given as w0h0 are derived by
_image_dimensions and capped to a maximum display width, and they
become the width/height attributes of the output format image display).

(assisted by Claude-Code)

1 files changed, 18 insertions, 0 deletions

diff --git a/org/ocda_functions.org b/org/ocda_functions.org
index 4745bc5..71d1b97 100644
--- a/org/ocda_functions.org
+++ b/org/ocda_functions.org
@@ -3448,6 +3448,24 @@ SHA_256_Hashes_ obj_digest(M)(
       writeln("WARNING, image not found or unreadable: ", filename,
         "\n  ", file_with_path);
     }
+    /+ ↓ the image file's own pixel dimensions, which are not the display
+       dimensions carried by the markup (w##h##): those are author set, or
+       where given as w0h0 are derived by _image_dimensions and capped to
+       a maximum display width. Header read only, no decode.
+    +/
+    if (!_file_info.fileMissing) {
+      import imageformats;
+      int _w, _h, _chans;
+      try {
+        read_image_info(file_with_path, _w, _h, _chans);
+        _file_info.imageWidth  = _w;
+        _file_info.imageHeight = _h;
+      } catch (Exception ex) {
+        debug(images) {
+          writeln("image dimensions not read: ", filename);
+        }
+      }
+    }
     return _file_info;
   }
   obj.metainfo.sha256.text = obj.text.sha256Of;