Philip Lenssen conducted a Q & A round with Radhika Malpani, Google's Senior Staff Software Engineer regarding Google Image Search.
According to Malpani, Google Image Search is the best option as the folks at Google "focus on comprehensiveness, relevance, and user experience. According to our internal testing, we score the highest when it comes to all 3 factors combined." "We have created advanced proprietary technology that checks keywords and phrases, URLs, and the image itself" came the reply when asked how Google managed to filter out adult images for non-adult search queries, when compared to other search engines.
Currently, the available modes through which users can specify Image Search Engine Results are:
show everything (the default old search)
show news images.
When asked about the future of Google Image Search, Malpani said, "As images continue to improve with the advances in digital photography, dimensions will likely change over time."