Image credits

These photographs illustrate the subjects discussed. Images of equipment are representative examples; their use does not imply that Real Prep has tested or endorsed the photographed model, or that the photographer endorses Real Prep.

The copyright and licence for each photograph remain as shown below. Where a photograph is offered under a share-alike licence, the adapted photograph remains available under that licence. The photographs were resized and converted for use on the site; any additional framing is identified.