After uploading, and on the embed links page, choose the "BBCode full fix HxW" option.

[img height=168 width=619]https://www.talkimg.com/images/2023/06/30/S4ClN.png[/img]
If you want to adjust the size, just change the height and width number. Try to choose a number that is proportional or, if you prefer, define just one of them, so that the image looks good.
Wow, this feature already exists. Sorry I didn't see that setting when using the talkimg service