Imported sprite gets compressed - Is it possible to turn it off?

Hey guys,
I just imported spritesheet with the dimensions 504x3186. I know, kinda big image but I am currently just testing around.
Now when I take a look at the imported image, Unity tells me the size of it is 128*1024. Also, the file size went from 366KB to 85KB. The results are blurry sprites.

How can I turn off the compression when importing image files?

Select the texture and change the Texture Importing settings, more information: