All the images I post should be printer-friendly (albeit print-only) JPG file. They are designed to be printable on a single page "as is".
On Windows: right-click on the image (in the forum) and select "Save image as", then open the saved file with Paint - if Paint is your default image editor then just right-click in Explorer and choose Edit from the context menu.
To print - first enter Page Setup (from the File menu), and make sure the Scaling option is "Actual size". Then set the orientation and centering options. If the image preview doesn't show it comfortably within the page, check the Margin settings, they may be excessively large (the default values typically are).
This procedure should have an analogue on any system.
Hope this helps!