Help with physical size conversion of PNGs

[u/Hardcoreoperator]

Hi!

A while ago I burned some CDs and made some artwork for them in Krita, and everything went smoothly. But recently I tried to do it again and when I converted my PNGs to PDFs for easier printing, the sizes were all off.

My pixel to cm conversion (and dpi) is identical to last time when it worked, but when I open the PDFs in chrome and check the actual size of them, they're different. I havr no idea why, but I'm hoping someone has a good way of converting PNGs to PDFs and keeping the size correct!