What about that drawer or photo album filled with all those prints? The ones that have been sitting there for 25 years? For that you will need a scanner. Scanners used to be expensive items, but not anymore.
Most printers are now sold as an All-In-One device. They can copy, print and fax. The scanners in these are capable of producing high quality digital files that can be uploaded to photo sharing sites like Google+, Flickr and Facebook.
The secret is configuring the settings. My scanner has presets like "Picture to File", and "Picture to Email". I ignore these because I feel the scan quality is set too low. I've settled on 300 DPI for my scan settings. That setting is specified in "Advanced Picture Settings". I have selected file type to be TIF instead of JPEG because I intend to do post-processing and a TIF file is lossless (uncompressed). Most normal people will set this to JPEG (I am not normal).
I suggest that a preview view be chosen for the scan. The software will attempt to find the borders of the photo but usually some adjustments will be needed. Mouse over the black squares to re-adjust the selected area. The selection area is delimited by "marching ants" which can be readjusted to select the parts of the scan you wish to save. This application also allows some image adjustment, brightness, color etc.
Click finish and you have your digital file.