I am used to using centimetres and pixels/cm and not inches.
How can I change this so that it remembers these settings every time?
In PagePlus there's an option under Tools, but in PhotoPlus all the items on the tools toolbar are functions.
I am using PhotoPlus X2
I'm sorry that I have mislead you. Go to Preferences / Layout and change the rulers/grid to centimetres. Click OK.
Using one of your pictures go to Image and click image size. You should now have the image size in pixels, the width and height in centimetres and the resolution in pixels per inch. I have not been able to change the resolution size as I think that resolution in pixels per inch is a standard measure. In the help files about resolution I think you will see it quoted as dpi - dots per inch.