For the needs of the site on which images are sold online

For the needs of the site on which images are sold online, create a part of the base where the Gallery data (image owners, at least 2), Images (at least) are stored. 15) Authors (at least 3). Example procedure: based on the name of the gallery, show all their images and authors of these pictures. Example Function: Based on the name of the author, show the average price the painting.