Quote:...Btw, are there any good tutorials you guys recommend?..
I can not recommend anything other than you might pick up some general ideas.
The problem with tutorials is:
Text tutorials, a good idea, the user can take some time studying the requirements. However I find that, invariably some step (vital or otherwise) is omitted leaving a 'how-did-they get-there' feeling. Then of course many are still showing Gimp 2.8 interface (sometimes even Gimp 2.6) Not the same as Gimp 2.10, you need to read-between-the-lines. If you go to gimpchat.com there is a section just for text tutorials.
Video tutorials. Might be quick but all the stages should be there. Same applies about Gimp versions, still some Gimp 2.6 around.
Usefulness: 99% are very specific with a carefully chosen subject. Carefully chosen to give a good result. Not always possible with more common images. Then, sorry to say, the ones that are more interested in advertising revenue than content. Often give poor / incorrect advice.
Just browse around and try and find something applicable. Need more advice? Ask a specific question on one of the Gimp forums. (I would avoid reddit, few sensible contributors there, only Ofnuts and a couple others.)
Anyway, Since liquid-rescale does not work in Windows Gimp 2.10.18 then with the example given a copy-paste will give a result. Needs resynthesizer / heal-transparency.
https://youtu.be/TRK0sADEwPU duration 3 minutes
Do not expect it to work with a busy / complicated background. Sometimes the easiest way is extract the subject and completely replace the background.