how to find dpi in photo

You can try using the shortcut Command + i, and this will pull up the information of the picture

If this doesn't work for you, then you could try consulting this forum how do i find out the dpi of a an image on my i mac

Photos in your library do not have DPI

DPI is Dots per Inch so until you add inches (the print size) you only have Dots (pixels) - once you know the print size as your remember form fifth grade math per means divide so you divide the Dots (Pixels) by the inches and you have DPI

DPI is the answer to a math calculation - not a property of an image

for a longer discussion see http://www.rideau-info.com/photos/mythdpi.html

LN