Every designer's been thoughtless in their choice of stock images and realised it could make it easy to misconstrue the meaning of a piece – and we've just received a prime example.

Flicking through this morning's pile of review books, I came across Graphic Design Rules: 365 Essential Design Dos and Don'ts. It's a flippable tome with a lighthearted approach covering sensible-if-a-little-obvious advice from 'Thou shall specify at least one plate as 100% tint for coloured type' to 'Thou shall not use Photoshop filters to disguise a low quality image'. A few need corollaries, for example 'Thou shall not design for print using system fonts' (um, Helvetica is a system font) – but overall it's a good book for business people you need to know the basics.

And then there's this piece of advice: 'Thou shall remember that people like bright things – brown is not exciting'. Which seems a fair point, backed up with a sensible explanation that babies prefer brightly coloured mobile in their cots to ones with muted tones – until you notice that its accompanied by a photo of a black or mixed race baby. Oops.

We're guessing the designer didn't mean any racist connotations from his choice of images. On book projects, stock images can have to be chosen quickly to meet deadlines, using keywords from the copy. Time to think about how such images are used can be fleeting.

But alongside 365 graphic design rules: I'd add a 366th: 'check that your choice of stock images couldn't be considered racist'.