Celebrities such as David Beckham use the law to protect their image
Royalty, celebrities, sports personalities, and the man walking down the street. All might see their photo being used without having given their permission - so what are the rules?
If Princess Anne believed a company had used a caricature of her to sell crisps, she could call on the power of Buckingham Palace to take action.
Celebrities such as Eddie Irvine have fought high-profile court cases in a bid to stop advertisers using pictures of them.
But who actually owns our image - and what can we do to stop our picture being used for something we disagree with?
As far as adverts are concerned, the Advertising Standards Authority (ASA) has a strict code covering the issue.
Spokesman Matt Wilson says: "All advertisers should get written permission from people whose image - whether it is a photograph or a recognisable caricature - is to be used in promotional material.
"If this hasn't been done there are a number of measures available to us, starting with simply talking to the company involved.
"Most of the time that will be sufficient - usually it has been done inadvertently and once advertisers are alerted to the issue they will take the appropriate action."
If a firm did not do this, it could ultimately find itself being referred to the Office of Fair Trading - in the case of print advertising - or Ofcom - for broadcast adverts - which could force it to stop using the disputed image.
However, in a recent case the 1970s runner David Bedford complained to Ofcom that directory enquiries firm The Number 118118 had used his image in its adverts without obtaining his permission.
Ofcom agreed that the company's ads breach the advertising code by caricaturing Mr Bedford - although it said this may have been unintentional and it found no evidence Mr Bedford had suffered financially as a result.
For this reason and because he had taken six months to complain, Ofcom ruled it would be disproportionately damaging to the company to stop it using the campaign.
A further problem is that while the code covers everything from TV ads to pictures in holiday brochures, it does not cover packaging which is not shown in ads or images which appear on a company's own website (pop-up adverts or ads on other websites are covered).
Princess Anne, who reportedly believed she had been caricatured on a packet of crisps by snack firm Jonathan Crisp, was able to turn to guidelines set out by the Lord Chamberlain's office which cover the way royals are used for promotional and commercial purposes.
A palace spokesman says the guidelines are flexible - and were relaxed during Golden Jubilee year - but that it was relatively unusual to find they had been breached.
"I would guess advertisers are fairly aware of what they can and cannot do and tend to stick to the rules. When they haven't we are usually able to reach some agreement."
In this case, the company said it was reviewing the design after a "cordial conversation with the palace".
However, for those without protection from the Lord Chancellor's office, the issue is less clear.
Leigh Ellis, from London-based intellectual property law firm Kaltons Solicitors, says that in addition to the advertising code, celebrities such as David Beckham could turn to the law of "passing off".
Formula 1 star Eddie Irvine used this to demand compensation from radio station Talk Radio - now TalkSport - after it used a doctored image of the driver in an advertising campaign.
The High Court eventually awarded him £25,000 - the amount the court believed he could demand to endorse a product in this way.
"The problem is that it is much harder for someone like you or I to show that the use of our image has had a negative effect on our reputation," Mr Ellis says.
"On the plus side, because our image does not carry the same sort of commercial value as that of someone like David Beckham, it is much less likely that any firm would be determined enough to use it because the negative publicity would outweigh the benefits."