[Feature Request] 请添加自定义模型的图片和文件输入功能

[haso2007]

🥰 Feature Description

由于一些原因，例如使用openai格式的Gemini调用，在使用nextchat是只能使用自定义模型，而nextchat的自定义模型不支持图片或文件输入，这就限制了使用自定义模型时的可用性。

🧐 Proposed Solution

自定义模型时默认使能图片和文件输入，例如gpt-4o一样的界面即可。

📝 Additional Information

暂时没有

[Issues-translate-bot]

Bot detected the issue body's language is not English, translate it automatically.

---

Title: [Feature Request] Please add the image and file input function of the custom model

🥰 Feature Description

Due to some reasons, such as using Gemini calls in openai format, you can only use custom models when using nextchat, and nextchat's custom models do not support image or file input, which limits the usability when using custom models.

🧐 Proposed Solution

When customizing a model, image and file input are enabled by default, such as the same interface as gpt-4o.

📝 Additional Information

Not available at the moment