Hello,
I recently decided to create a showcase for one of my sites. I needed a row of five thumbnail images of my products, randomly displayed.I

thought it would be easy to find this PHP code, but this turned out not to be the case, Can you show me some tips thanks in advance.

You can create showcase using joomla.See the following tutorial:
learning.cloudaccess.net/knowledgebase-documents/90-core-joomla-functions/modules/78-how-to-create-a-showcase-module-using-a-cloudaccessnet-template-joomla-25.html