seo – Change the names of the images or create a sitemap for the images? Or both?

The environment is a classified ad site, where there are products with their description, title and photos. With the exception of images, all data is stored in a MySQL database.

Although there are user-friendly titles for classifieds and it's relatively easy to link them, all images are saved with a randomly generated name (something like d6as897d6ad67a5s7da8d56sa7d.jpg).

The question here is, for SEO, PAGE RANKING and SERP pages, what is the best thing to do and why?

  • Change the names of random character images to classified titles;
  • Create a site map image;
  • Both.

What are the disadvantages and advantages? And why not choose the other options? Are there any other alternatives that I have not mentioned here?