Preparing photographs for sale involves the image, the product description and clear usage terms. First decide whether the transaction concerns a physical print, a digital file or a licence to publish an image.
Describe what the buyer receives
State dimensions, format and any relevant print details accurately. For digital use, distinguish file delivery from permission: the licence should explain the allowed use and any limits. Keep credits and rights information attached to the transaction.
Present a coherent selection with consistent previews. Check that the preview represents the delivered crop and colour, and make the practical details easy to find before any purchase is made.