One of the things that spam filters look at is the text:image ratio of your email. Did you know that? If you’ve ever gotten one of those spam messages which has a big old image, and only a little text, or perhaps even one of those spam messages where the text is embedded in an image, you can understand the reason for this. It’s because spammers likes to send messages with images and little text – because of course the spam filters are analyzing their text.
So, if you send email which has a high image-to-text ratio, the spam filters are more likely to think that your email is spam, and send it to the junk folder. They may even come to the conclusion that you are a spammer, and block you.
Of course, the answer is not to add a bunch of random text to go with that image.
Because spammers do that, too.
It’s also important to remember that if you include an image file as an attachment, many spam filters and virus checkers will junk your email because it has an attachment.
On the other hand, if you simply include a link to a graphic file hosted elsewhere, that will increase your text:link ratio, which can also cause problems. So can an out-of-balance text:code ratio generally.
The message here is to be aware of your text:image ratio (and text:link ratio). Don’t go sending a bunch of images with relatively little text. And if you think about it, for most commercial email – such as an email marketing campaign, or ecomm email – there should be more text than images anyways. There should also be more text than links. Because it is copy which convinces. And it is copy which compels. And that’s what your email needs to do to keep getting delivered to the inbox (and to keep generating sales): convince and compel.
Unfortunately there is no hard and set rule as to what a safe ratio is, but a good rule of thumb for general email marketing is to have at least 200 words for every link and/or image, and a good rule of thumb for ecomm is that you want at least one paragraph of text for every image and every link.
In the end, the bottom line is that you should err on the side of being judicious with your use of images and links in email, and remember: email is the place to drive people to your website; your website is the place for all of those pretty images and any links that don’t go to your own site.