can it be done

I used the original image from Joomla, only resized it in Adobe Photoshop and gave it here: my_default_template : Template created in Template Creator CK latest release
But I am now wondering about the option you wrote about at the beginning And now if to this folder: > I will add a new flagio image, I will name it e.g. 2-en_gb.gif
And here I will select it from the drop-down list: Should that work too and Works fine with no problem.

Only one question at the end
Is the language flags image used in Joomla backend the same image that is used later (front side = all pages in front)
Why in a folder "media/mod_languages/images/ " there are two .gif images for one language version

ok, using template creator, the correct path is
templates/YOUR_TEMPLATE/images/mod_languages
this is because in template creator I don't use the media folder (for now)
tested by my side, this works

templates/YOUR_TEMPLATE/images/mod_languages

It works perfectly, that's exactly what I was looking for. Thank you very much for your help