Translation:
Firstly, we would need more information to address your issue. Please let us know which website you are using and what method you are using to upload the background image.
Generally, website updates can bring about some changes. If you are unable to upload a background image, it could be due to some issues during the update. However, we cannot determine if it is a bug without further details.
To assist you better, please provide the following information:
1. The name and version number of the website you are using.
2. Specific issues you encountered when attempting to upload the background image.
3. The method you previously used to successfully upload a background image.
Once we have more details, we will try our best to provide a more accurate answer. Thank you!