Describe the bug
对于没有后缀的图片链接保存在本地为 null 导致上传第三方储存桶报错
To Reproduce
Steps to reproduce the behavior:
飞书粘贴到Typora的链接大致如下
2026-02-27 20:51:00 [PicList INFO] [PicList Server] is listening at 36677 of 127.0.0.1
2026-02-27 20:51:00 [PicList INFO] Web server is not enabled
2026-02-27 20:51:00 [PicList INFO] File server is running, http://localhost:36699
2026-02-27 20:51:21 [PicList INFO] [PicList Server] get a POST request from IP: 127.0.0.1
2026-02-27 20:51:21 [PicList INFO] [PicList Server] get the request {"list":["\/var\/folders\/8r\/xxxxxxxx\/T\/abnerworks.Typora\/(null)"]}
2026-02-27 20:51:21 [PicList INFO] [PicList Server] upload files in list
2026-02-27 20:51:21 [PicList INFO] Pre-processing images, please wait...
2026-02-27 20:51:21 [PicList INFO] Remove exif info
2026-02-27 20:51:21 [PicList INFO] Transforming... Current transformer is [path]
2026-02-27 20:51:21 [PicList INFO] Before upload
2026-02-27 20:51:21 [PicList INFO] beforeUploadPlugins: renameFn running
2026-02-27 20:51:21 [PicList INFO] Uploading... Current uploader is [aws-s3-plist] with config id [da14867b-8337-4528-bb07-1f99ce3be806]
2026-02-27 20:51:23 [PicList SUCCESS]
https://image.xxxxx/xxxxxxxxxx.webp
2026-02-27 20:51:23 [PicList INFO] delete local file: /var/folders/8r/xxxxxxxx/T/abnerworks.Typora/(null)
2026-02-27 20:51:24 [PicList INFO] [PicList Server] upload result https://image.xxxxx/xxxxxxxxxx.webp
-------同一张图片上传后再次右键上传（此时已经有后缀了）------
2026-02-27 20:56:11 [PicList INFO] [PicList Server] get a POST request from IP: 127.0.0.1
2026-02-27 20:56:11 [PicList INFO] [PicList Server] get the request {"list":["\/var\/folders\/8r\/xxxxxxxx\/T\/abnerworks.Typora\/xxxxxxxxxx.png"]}
2026-02-27 20:56:11 [PicList INFO] [PicList Server] upload files in list
2026-02-27 20:56:11 [PicList INFO] Pre-processing images, please wait...
2026-02-27 20:56:11 [PicList INFO] Compress or convert image
2026-02-27 20:56:12 [PicList INFO] Add watermark to image
2026-02-27 20:56:12 [PicList INFO] Transforming... Current transformer is [path]
2026-02-27 20:56:12 [PicList INFO] Before upload
2026-02-27 20:56:12 [PicList INFO] beforeUploadPlugins: renameFn running
2026-02-27 20:56:12 [PicList INFO] Uploading... Current uploader is [aws-s3-plist] with config id [da14867b-8337-4528-bb07-1f99ce3be806]
2026-02-27 20:56:14 [PicList SUCCESS]
https://image.xxxxx/36100ce9918e4f2d9ea472d487beb773.webp
2026-02-27 20:56:14 [PicList INFO] delete local file: /var/folders/8r/xxxxxxxx/T/abnerworks.Typora/xxxxxxxxxx.png
2026-02-27 20:56:14 [PicList INFO] [PicList Server] upload result https://image.xxxxx/36100ce9918e4f2d9ea472d487beb773.webp
Expected behavior
通过文件头的 magic number（如 89504E47 = PNG, FFD8FF = JPG）识别出常见真实的图片格式；或者通过响应的content-type 提取后缀
Screenshots / Screencasts
If applicable, add screenshots / screencasts to help explain your problem.
Sample Markdown File
Please attach or send us hi@typora.io the sample md file that may reproduce this.
Desktop (please complete the following information):
Typora Version
e.g: 1.13.0-dev (7622)
Additional context
Searched existing issues to avoid creating duplicates.
Confirmed that it can be reproduced in built-in themes without customized css.
If it only exists in 3rd party themes or css, you can still report it, but please attach the theme target or the css file. We may not "fix" it, if it is caused by 3rd party themes or css styles that we cannot support.
Searched http://support.typora.io/
Describe the bug
对于没有后缀的图片链接保存在本地为 null 导致上传第三方储存桶报错
To Reproduce
Steps to reproduce the behavior:
Expected behavior
通过文件头的 magic number（如 89504E47 = PNG, FFD8FF = JPG）识别出常见真实的图片格式；或者通过响应的content-type 提取后缀
Screenshots / Screencasts
If applicable, add screenshots / screencasts to help explain your problem.
Sample Markdown File
Please attach or send us hi@typora.io the sample md file that may reproduce this.
Desktop (please complete the following information):
Typora Version
e.g: 1.13.0-dev (7622)
Additional context