By using a specialised suite of software it is possible to enlarge images many times whilst retaining and even improving detail and quality.
The following pictures have been obtained using Google search. The originals are about 5.5cm x 4 cm each and a resolution of 72dpi. They have all been "cleaned" up and enlarged 6 times to about 32cms x 24cms up to a resolution of 300dpi, meaning they are suitable for printing at that size. 
As can be seen the photos, even using low resolution web originals, are not only larger but are clearer and sharper. However, by copying or scanning original photographs it is possible to make far larger enlargements and ensure even better detail.
Click on the images for a larger picture

The ability to colourise prints brings a new dimension to old faded photographs