Done! Done! Done!
Well, since no one wanted to help, I did some work on it myself.
It may not be perfect, but it's good enough for me.
Thanks but no thanks!

Hi,

i've a background tileset from  https://pixel-boy.itch.io/ninja-adventure-asset-pack (NinjaAdventure(SupporterEdition.zip)) and need someone who can change it so that I can use it - as an example - so that sand and ice merge into each other and that in the same map.
So some tiles need to be a merge.
So there should be no hard edge from the sand tile to the transition in snow.

Sand and snow are only examples, there are mud and grass also too.

The creator of this tileset is looking for some help, so i didn't contacted him because they will not change anything right now because of time i think.

PS: English is not my favorite language, so if you don't understand, ask.