did someone know why this is not Working if i rename it into Blau? Ver 1.12.2
Well for starters, it doesn't look like your image file is a perfect square which is essential to make a texture work in Minecraft.
For another, you're using capital letters in your file names. Minecraft is allergic to capital letters, so that'll automatically break whatever you're trying to do.
If you fix both of those issues and it still doesn't work, then post your new files (not just screenshots) as well as a session log (.minecraft/logs/latest.log) to pastebin or a similar site and provide a link to it. It's much easier to solve problems when we can get a better grasp of what you've done than just by looking at screenshots.