If I set the page background as a bitmap image, then save as DOCX format, the saved file lost its background.
Steps to Reproduce:
1. Download and open attachment 152249 [details]
2. Press Ctrl + Shift + S to save
3. Keep file name "wood", set file type as Word 2003-365 format
4. Press Ctrl + W to close
5. Open the Wood.docx again
No backgorund image on the page, open the file with 7-zip found no media folder within document
The backgorund image should properly stored into DOCX file.
User Profile Reset: No
Version: 184.108.40.206 (x64) / LibreOffice Community
Build ID: 614be4f5c67816389257027dc5e56c801a547089
CPU threads: 4; OS: Windows 10.0 Build 19043; UI render: Skia/Raster; VCL: win
Locale: zh-CN (zh_CN); UI: zh-CN
Version: 220.127.116.11.alpha0+ (x64) / LibreOffice Community
Build ID: 4677345e3695bac158bb04048b4d5c608ed764b4
CPU threads: 4; OS: Windows 6.1 Service Pack 1 Build 7601; UI render: default; VCL: win
Locale: ru-RU (ru_RU); UI: en-US
ID сборки: 3215f89-f603614-ab984f2-7348103-1225a5b
Not clear if you searched in reported bugs, I didn't test but seems duplicate by desc.
*** This bug has been marked as a duplicate of bug 126533 ***