@Karosnikov - I think you have it a little backwards - we're not talking about the dpi/ppi being important - we're talking about the actual pixel dimensions being important. In your example above, your image is 156x302.

Yes, your printer will print the physical dimensions in INCHES or CENTIMETERS based on the SETTING of the dpi - in which case as your example indicates will be 5.5x10.65CM. Change the dpi (while Resample is unchecked) to 300 and your printer will spit out a .52x1.006CM image - the 156x302 has never changed - just the SETTING of the dpi for your printer.

It's your job, as the artist, to make sure you have rendered to a sufficient size to begin with - not jjust some little rendering you hope will fit your target destination.

Before you render, you will make the decision of size - this shouldn't be "Oh, I'll justmake it this" because as a professional you should have some form of use for this once rendered (publication, wall prints, computer wallpaper - whatever). If this is for a specific printout - let's just say an 8x10 inch that at the end you want set to 300dpi - you will render the dimensions specifically for 2400x3000 pixels. It's math - not output resolution.

Pixel dimensions (3000x4000 as opposed to 156x302) - not dpi - is what matters most. You can always go smaller for your ouput aize - but going bigger is problematic as you introduce artifacts.