Images on the page do not have time to load - how to fix it?

Question

CodeIgniter

Hello world!
There is a table in the MySQL database (InnoDB), it stores about 30 million links to images. When loading a page (a site on codeigniter) on which they should be displayed, a problem periodically occurs: not all are displayed (only 15 on the page, weighing 15-20 Kb each). If you do F5 - then everything is loaded. The impression is that they simply do not have time.
How can this be corrected? Thank you.