To successfully print them, you must set the correct settings in the Print dialog. Different apps and different printer manufacturers will have slightly different settings; however, many share similar dialogs. You may need to set the orientation to LANDSCAPE, it may be auto-set and display landscape. Firefox may flip the image sideways and say it’s Portrait. Look at the preview to ensure it looks correct.   It also must be set to Fit to Paper, Fit to Printable Area, Shrink Oversized Pages, or something similar. You probably will need to click on the down-arrow More Settings to view these menu items. You can also set it to Color (optional), print all pages, etc.