Image size

Okay, I'm confused.
If I want to create a new image with Photoshop, I select 9 cm for both the width and the length. Then I set the resolution to 300 pixel/inch... this was the standart resolution, I was told.
But the final image is much bigger than 9x9 cm! What am I doing wrong?

Probably because 300 pixel/inch doesn't fit into 9x9cm?

sure it does, just not round. but really, wtf are you making the thing for? size is usually done in pixels but if you're going to print than you divide the size in pixels by the dpi to find how big it'll be when it prints.

Yes, it can. Size and resolution are two different things.

Resolution is only important if you´re going to print the file, if it is to use in a digital media just keep it in 72 dpi.

thank you

No problem :)