I opened an image in GIMP, clicked Image-->Image Properties, and it indicated that the resolution is 72x72ppi.

Opened same image in Photoshop, clicked Image-->Image Size, resolution is 180ppi. Why is that??

Thanks dawgs

I am not sure but if i understand PS assume that, if there are no indication of ppi a default value of 180, gimp does the same but there default is 72

Both allow you to chose any other value,

But the argument is quite complex also because ppi and dpi, that should be quite different things are communly used as were synonimous