tools · free, in your browser
set the ppi (change dpi).
the 72 in your file is only a label, but some print systems read it. set it to match your print size. your pixels are not touched, and nothing is uploaded.
choose a file first
why the ppi number matters, and why it doesn't
ppi (often called dpi) tells a printer how many of your pixels to put on each inch of paper. changing it doesn't add or remove pixels, so the quality stays the same. what it changes is the size some programs and print systems assume when they open your file.
to know how big your image can print well, use the free check. it reads the pixels, not the label.