scanned or photocopied photos is fine. If the Visa Office has any reason to believe a photo has been doctored or edited, they may request an original if the picture is important to proving a relationship (ie. wedding photo's).
I've only heard of the above situation happening a few times and in each case the original photo had been changed to represent a more favorable situation for the applicant.
All the photos I have are digital, so I used Microsoft Word to place 6 photos per page on the document, along with captions underneath with the specific date and a description of the significance of each photo.
I also know of many cases where people simple B&W photocopy photos and use that - so as long as you can make out what the photo is.