The Cobra Effect is a term in economics. It refers to a situation when an attempted solution to a problem makes the problem worse. This name was coined based on an incident in old colonial India.

Google is more likely to index bigger images compared with smaller once. May be when Google see's multiple images on a page, it decides not to index images with small resolutions.

Meta tags offer the website owner the ability to control some degree on how their web pages are described by some search engines. They also offer the ability to prevent pages from being indexed at all.