Wrong/Correct sized printing


I still use PSP7...The early 2000's program...It's my comfort zone.

One issue I have always had is printing the correct size. I want to print a photo to A4 size but when I do, it comes out slightly small.

Conversely, I tried to print a DVD cover, which was the correct size, it came from a company online that specialized in replacing DVD artwork covers, so they sent me the exact size I needed to print a cover that would align the spine of the cover, with that of the DVD case...Yet when I printed it, 3 times, each time the cover/picture came out slightly bigger...Even the spine on the picture was wider than the DVD cases spine.

I do have a copy of PSP9 again the early 2000's edition, so if there is an issue with correct sized printing using PSP7, I can use PSP9 just to print.

I'd like to also print smaller photos to fit in a multi frame, I'm not sure of the sizes but I think one size picture slot/hole is 3x3 inches

Do any of you have a step by step set of instructions to help me start printing to an exact size please ?

Thank you for reading this