@leocg
The same page - on the left Opera,
on the right Samsung app for Android 8.0

@leocg
Ok. Link below:
http://forum.swietageometria.info/index.php/topic,326.msg10506.html#msg10506

@leocg
I can see the thumbnails for the YouTube in
Chrome for Android,
Firefox form Android,
Samsung for Android,
but I can't see the thumbnails for the YouTube in Opera for Android
using that tag, of course.

The problem is, that there are appox 700 videos in the tag,
We like Opera. Everything works best on Opera except for these tags...

@leocg
Ok. Link below:
http://forum.swietageometria.info/index.php/topic,326.msg10506.html#msg10506

@leocg
The same page - on the left Opera,
on the right Samsung app for Android 8.0

Opera does not display YouTube videos embedded on smf forums using [youtube]...[/youtube] tags.
Opera for Windows works very well in this regard.
Please do it possible on Opera for android.
There are thousands users of this functionality.