I'm creating digital art in Krita which is printed in big sizes also(18"x24" 300 ppi).When I create the art I give the max dimensions to the image(18"x24" 300 ppi)
Now there are additional graphics and elements I want to add to the image-the graphics I want to add are 300 ppi but smaller in image size-so I need to scale them-so they fit my big document-I'm afraid that during the scaling of the external graphics their quality will be lost-I'm trying to understand what happens to resolution if scaling-My main concern is the quality of the digital art-the final product-I need it to be 300 ppi at big size(18" 24")so just want to understand the wise way to use external graphics -and how to scale them without harm to the resolution and quality-I'm trying to understand what happens to the quality when I scale this external graphics-do they lose their quality? Does their resolution change ? Does resolution in general changes during scaling?
maybe the solution is to embed vector graphics to the document and not raster?

Alinsh, you've been asking so many resolution related questions... Why don't you try making grayscale copies of your images and print them? You'll be able to see the exact effect of low resolution immediately then, and decide if you even care.

For vector graphics it won't matter as those have their curves recalculated. For vector graphics that have been rendered to pngs, those are raster graphics, so scaling down will always give better results than scaling up, regardless of resolution.