[Feature Request]: ComfyUI workflow manager wants to add thumbnail functionality

### Is there an existing issue for this?

- [X] I have searched the existing issues and checked the recent builds/commits

### What would your feature do ?

ComfyUI workflow manager wants to add thumbnail functionality
When facing multiple workflows, especially those with similar functions, the thumbnail of the workflow can assist us in making the right choices more easily.

### Proposed workflow

1. Right click options on images in the workflow have been added and set as thumbnail images for the workflow
2. Display the thumbnail corresponding to the workflow in the workflow manager

### Additional information

_No response_