How can I scan my photo at 72 dpi?

Jim wants to enter pictures in a photo show and the show wants them as JPEGs at 72 dpi. He has to scan his images to do it. Leo says that 72 dpi is at very low quality and it's obviously an online gallery. But he can scan his images at the highest resolution possible and save it in TIFF. That would be lossless compression. He can always open it in a photo editor and then lower the resolution to JPEG. Leo recommends Irfanview.