Oh , I had already seen this post and followed it too, but I think you did not got my point there. Whenever I execute those command , my old logo is only shown.
You can configure neofetch to show any logo you want it to, by editing the ~/config/neofetch.conf file. You can even (given specific capabilities in your terminal), have it show a .png file. What do you want it to show?
If you save the contents behind the arrow as ~/.config/neofetch/gar-txt4, then finding the place in the ~.config/neofetch/config.conf file where this goes (search for image_source) and set it to:
image_source="~/.config/neofetch/gar-txt4"
you will get that displayed. There are a lot of neat things in that file you can change - so have at it! That's one of the fun parts of Linux...
Well - that works - but there may be another setting in there that is overriding it - or perhaps you need to specify the path more explicitly ie: /home/username/.config/neofetch/gar-txt4 (where username is replaced by your username)
Create whatever you wish, and locate and name it in a similar manner. If you need to convert an image to ascii - there are websites for that. If you want to display an image directly, there is quite a bit of setup - and it tends to disappear when a key is hit after being 'presented'. The info is pretty good in the config.conf file - that's how I figured it out...