These options are not for Moodle sites that are entirely SSL, so if you're running the whole site as https, then disable them.
$CFG->sslproxy = false;
$CFG->loginhttps = false;
The pictures issue is caused by changing the URL from http to https. Essentially, when you change from http to https, you do a "migration" (https://docs.moodle.org/28/en/Moodle_migration) even though the files don't move. To fix the URL's inside the database, you need to run the search/replace tool. To do that:
- Log in as a site admin
- Go to: https://mymoodle.org.co/admin/tool/replace/index.php
- Search for http://mymoodle.org.co and replace with https://mymoodle.org.co