Teachers use the internet to obtain all kinds of images and there is a variety of search engines and image hosting sites available. Google, Yahoo and Bing are very popular and can locate thousands of images very quickly. What many don’t realise, however, is that they could be opening a Pandora’s Box of unsuitable, unrelated and potentially incriminating images through that simple search.

In searching for suitable images, the retrieval system will often return pictures that are unrelated to the search and which happen to be adjacent to the search keywords in a document or website. In addition, many retrieved images will often carry a copyright warning.

The moment you input your search term, dozens of images pour into your hard drive and stay there until they are wiped off or are overwritten by new material. For example, perform a search on Google Images for an image of US President Obama. The search engine reports that there are more than half a million images related to the search term “Obama”.

Scrolling down the page reveals a large number of images of President Obama, including a few that are not too complimentary. Even if you choose not to download any of them, they have made themselves at home on your hard drive in case you decide to do so at a later stage. This ensures that they will load quickly.

Unless you are a particular admirer of the President, the only reason you have collected over 200 images of him is because of your search, and they will stay there until you wipe them with drive cleaning software or the computer overwrites the space they occupy. If someone searched your hard drive with a program designed to recover images or documents that have been saved but deleted, they would still discover 13 pages of Google Images bearing Obama’s face, even if you have only seen a few of them and used just one for your lesson.

Cleaning the cache will not remove the images, just the reference data about them. Incidentally, the same search on Bing Images stores nearly 1,000 Obama-related images on your hard drive, and if you have a lot of free space there these uninvited visitors may stay for months or even years.

There is minimal risk in searching for images of the US president, but problems can arise from the most unexpected of search topics. As a child, a friend was stung by a scorpion and recently told one of his grandsons about it. Though the sting was not serious, the boy wanted to know what a killer scorpion would look like and how large it would be. Turning to the internet, my friend entered the search term “killer scorpions”. The image search responded with a display of rather menacing looking creatures, the exhaust of a motorbike, and images of a naked prepubescent girl in a sexually provocative pose. Scrolling through, there were almost as many images of this young girl as there were scorpions. Her presence on this search is explained by the fact that she had been used to illustrate the front of a record album by a group called Scorpions. Later, when this search was repeated on another computer and the hard drive inspected using cleaning software, more than 100 images of the girl were discovered. Legally, these would be classified as indecent images of a child and the computer user could be prosecuted for possessing them.

In 2008, the Internet Watch Foundation (IWF) blacklisted the image on Wikipedia, an action which resulted in an escalation of internet viewing. A few days later, the IWF reversed its decision “in light of the length of time the image has existed and its wide availability”.

Most image searching systems offer an option called safe search and this usually operates as the default setting. Automated methods and algorithms are used to identify objectionable content, but it is never entirely clear how a system decides that a particular image is suspect and must be blocked. For example, on Google, the search term “fat lady” will produce a host of images, some tasteless, straight away. On Bing, however, no such search is possible until the safe option is removed, only for the user to be confronted by a considerable amount of pornography.

It is also worth noting that an apparently “safe” search will not always be so. To illustrate an article on corporal punishment in a military school during the 1950s, I found an image of a rather unhappy boy in uniform about to be caned. It was the second image to appear in the search and met my requirements perfectly. What was not seen, however, was the torrent of images that followed it on to the computer’s hard drive, many of which could only be described as sordid and disturbing. This was a “safe” search.

There are also many search terms which can give rise to ambiguities. Pageant, for example, has a rather different meaning in the US and a searcher in the UK will not normally expect to retrieve images of little girls dressed like prostitutes.

Similarly, teachers wishing to illustrate a recipe of a delicious bombe surprise will certainly get a surprise when confronted with the contents and workings of an individual explosive device. Google for a side profile of UK Prime Minister David Cameron and you may be lost for words unless you happen to be a urologist.

Teachers, more than anyone, need to be particularly careful about their personal internet communications and searches. The recent case of a teacher who joked on Facebook that her pupils were less intelligent than pigeons - causing an outcry from parents - is a case in point. Vent your frustration in immoderate terms on Twitter, or an internet forum, about someone or some organisation, or send your computer for repair or transfer it to a new owner, and any of these scenarios, no matter how innocent, could result in a search warrant being issued and the computer being seized for investigation.

This is not a fantasy; it is happening all the time and, nationally, there is a huge backlog of seized computers awaiting inspection. Some of those who have aroused suspicion have eventually proved their innocence, but at considerable cost to their finances, reputation and freedom.

So while you believe it to be an innocent search for images to illustrate worksheets or revision notes - be careful. To ensure that you are not harbouring uninvited guests on your computer, use a private browsing facility on your browser, invest in some drive cleaning software and use it on a regular basis. Be vigilant. Think about that search term, and check for any typing errors before you press Go.

Tony Crowley is a retired writer and illustrator

SEARCH ENGINES FOR CHILDREN

- Ask Jeeves for Kids: www.ajkids.com

- Yahooligans: http:yahooligans.yahoo.com

- Safe Search http:primaryschoolict. comsuperhi.php

TECHNICAL ADVISORY SERVICE FOR IMAGES

The TASI website provides advice, training and resources on using digital images in education. Although primarily aimed at the further and higher education communities, the site also provides information of use to primary and secondary teachers.

www.jiscdigitalmedia.ac.uk.