The image retrieval function in the knowledge base retrieval section is not working properly

### Self Checks

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### Dify version

17.1

### Cloud or Self Hosted

Self Hosted (Docker)

### Steps to reproduce

During the process of knowledge base retrieval, it was found that some images could not be rendered normally. Upon examining the returned URLs, there was no difference in structure compared to other URLs that could be rendered. Additionally, the original image was found through a key query in the database. Therefore, there should be no issue with the original image URL. Considering whether it was returned by Dify itself

### ✔️ Expected Behavior

I hope this issue can be resolved as soon as possible

### ❌ Actual Behavior

_No response_

Reproduce the problem in the Dify 17.1 self-hosted Docker setup during knowledge base retrieval, comparing an image that renders with one that does not. Inspect the returned image URLs and the corresponding database records first; done means the affected images render normally through the retrieval flow.

Written by the indexing model from the issue text.