Greasy Fork is available in English.
Download images, GIFs, videos, and voice messages on the Telegram webapp from private channels that disable downloading and restrict saving content
< Feedback on Telegram Media Downloader
It's not working now even after cached.
I tried it, and the script can be used normally, but the premise is that the picture or video must be cached on the webpage before clicking download, and it can be saved directly at this time.
It is not very friendly for larger media files, and must wait for him to be cached instead of downloading in the background.
I don't know if the author can improve it
我尝试了，脚本可以正常使用，但前提是图片或视频必须在网页上缓存完毕才能点击下载，此时可以直接保存。
对于较大的媒体文件就不太友好了，必须等他缓存完毕，而不能在后台下载。
不知道作者能不能改进一下