Email marketing providers should always remember that messages may show up differently in individual inboxes, it has been claimed.

Industry commentator Simms Jenkins noted that where images in particular are concerned, marketers should be wary of the end presentation.

Writing for ClickZ, he noted that many users' browsers may be unable to support pictures, or may simply choose not to accept particular visual displays.

Mr Jenkins noted that as few as a third of internet users have images turned on by default – potentially meaning marketers must strike an effective balance between written content and visuals.

Failing to dedicate enough time to producing high-quality text, in favour of concentrating on images, may prove to be a mistake if the reader cannot view the email in the format intended, he suggested.

Last week, the Direct Marketing Association warned that poor email marketing can damage firms' reputations and ultimately their bottom line.