ods save leak

I am seeing the following leak when saving to ods. A similar leak does not occur when saving to .gnumeric so the assumption is that something grabs an extra ref somewhere.

../tools/gnmvalgrind --leak-check=full ./ssconvert ../samples/excel/objs.xls /tmp/fff.ods
[...]
==631048==    at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==631048==    by 0x58D5E98: g_malloc (gmem.c:102)
==631048==    by 0x58EE485: g_slice_alloc (gslice.c:1025)
==631048==    by 0x58EEAAD: g_slice_alloc0 (gslice.c:1051)
==631048==    by 0x585913F: g_type_create_instance (gtype.c:1850)
==631048==    by 0x583834C: g_object_new_internal (gobject.c:1937)
==631048==    by 0x5839B44: g_object_new_with_properties (gobject.c:2105)
==631048==    by 0x583A6F0: g_object_new (gobject.c:1777)
==631048==    by 0x4F2B3CC: go_pixbuf_new_from_data (go-pixbuf.c:391)
==631048==    by 0x4F29CC0: go_image_new_from_data (go-image.c:666)
==631048==    by 0x4A05BBC: sheet_object_image_set_image (sheet-object-image.c:144)
==631048==    by 0xE6241C5: ms_sheet_realize_obj (ms-excel-read.c:671)
==631048==    by 0xE61AE02: ms_container_realize_objs (ms-container.c:166)
==631048==    by 0xE62CBFF: excel_read_BOF.isra.0 (ms-excel-read.c:7143)
==631048==    by 0xE62D828: excel_read_workbook (ms-excel-read.c:7249)
==631048==    by 0xE6183BB: excel_enc_file_open (boot.c:192)
==631048==    by 0x4E9F04E: go_plugin_file_opener_open (go-plugin-service.c:686)
==631048==    by 0x4A6EFC1: workbook_view_new_from_input (workbook-view.c:1387)
==631048==    by 0x4A6F24E: workbook_view_new_from_uri (workbook-view.c:1459)
==631048==    by 0x10FE31: convert (ssconvert.c:1207)
==631048==    by 0x110AE4: main (ssconvert.c:1519)