In the perfect situation you'd have unlimited time and money available when creating a presentation, print document or online learning materials. You'd be able to call in whatever specialist expertise you wanted and have the time to wait while they delivered the goods. When it comes to the sourcing of visual aids, you would not hesitate to have a photographer carry out a photo shoot (even if this involved hiring models, booking studios, elaborate location shots and endless Photoshop manipulation of the results); you'd have no qualms about asking a graphic designer to put together complex Flash animations or an illustrator to do, well, illustrations.

I know that visuals are often used for the wrong reasons, typically as a form of decoration or as a way of filling a space. But in more cases than not, visuals are a necessary ingredient, because words alone just wouldn't do the job. Visuals can explain what words can not and are much more likely to be remembered. But of course you can't just use any old visual - it has to fit the purpose.

So, given you haven't got the time and the money for specialist help, what can you do? Well, sometimes you can strike lucky and find exactly what you want on Google Images or in your organisation's own image library (chance would be a fine thing); you could take your own photos or knock up a simple chart or diagram in a graphics programme. But in my experience that leaves an awful lot of gaps. That's when I turn to clip art and stock photography.

There's a lot of snobbery about this. Obviously the professionals discourage it, because it means less work for them, just like the live bands complained when discos first appeared. And there's a lot of poor clip art and stock photography out there which is horribly cheesy and, worse still, over-used. But given all these provisos, I still have no hesitation in using it because (1) it has after all been created by professionals and (2) it often does the job just fine. It's simply a case of being pragmatic and proportionate. What's so wrong about that?