So, this might be a dumb question, but when creating a new image, you set height and width and also resolution. But what exactly is resolution? Isn't resolution simply height * width? Then why can I set a custom resolution apart from height and width? What should I set resolution to, how is the image effected by the resolution and how should the resolution follow height and width? And what is resolution? Number of pixels?

Resolution tells you how much pixels will be printed in one inch of a paper. It just provides a link between pixels (which are virtual measurement) and the real life measurements.

Unless you prepare stuff for printing, you don't need to care about it. Just let it be those 300 or something.

Resolution is the number of pixels per inch: see https://docs.krita.org/en/user_manual/w ... on#dpi-ppi

But does that mean that the higher the resolution the better the image quality? I mean, can I tell the difference if I have a 1000 * 1000 image with resolution either 50 or 300 or 900? And should I just keep 300 as default for all images regardless of size or should resolution scale with height*width

Unless you intend to print, there's no point worrying about dpi. All that matters is how may pixels are on the screen. A 1000 x 1000 pixel image will always look the same on your screen but will look bad if printed on a full sized sheet of A3 paper and will look sort of ok but not fantastic if printed full sized on A4 paper.

If you intend to print, then the dpi figure is useful for setting up an image with the required dpi for a given size of printed final image.

In general, for home printing, 300 dpi is more than good enough but some people like to work on-screen at 600 dpi then scale a copy down to 300 dpi for printing. Actually, the printing application and drivers do all the scaling you need. If it looks good on a normal sized monitor, it will look good when printed on A4 paper.

Unless you have an amazing printer with amazing inks and amazing paper then 900 dpi is not something you need to think about.

Alright, thanks a lot for all the help!