In email clients that block images by default, such as Outlook 2003, a recipient can read an entire column, in either the message preview pane or when it is opened. The image-based ads or flashy photo will not appear
An estimated 95 percent of all commercial email messages are sent in HTML or combined with text format. Most email includes at least a single external image, which may be an open-tracking image, to track whether an email has been opened, or not.
External images include logos, masthead or header images, and product or people photos. Virtually all email marketers host images on a Web server, rather than embed them within the message itself. To load images, a call is made back to the hosting server. Many ISPs and some email clients block this call.
The primary reasons behind image-blocking features are to enable users to prohibit adult and pornographic images from loading and to prevent spammers from knowing if users open their messages. The latest versions of many major ISPs' email interfaces and email clients automatically block any external image In addition to Gmail, there are other ISP clients like Windows XP Service Pack 2 upgrade that has added the blocked images feature to its Outlook Express.
Disabling the images can affect the email marketers a lot. Here are a few of these affects.
For ad-supported newsletters, disabled images means hosted ad formats are not displayed. Hence, no clicks for advertisers.
Most of the e-commerce oriented marketers who use aggressive promotional copy repeatedly throughout their messages have significant problems with content-based filters. Some recipients scan email in the preview pane or open messages with images disabled. Marketers may have experienced a slight decline in open rates in the past year or so due to this.
Some ISPs and email clients enable users to determine if they want images blocked. So knowing which ISP a subscriber uses may shed little light on whether the message had ‘images enabled’ For example Yahoo options. Don't block any images It may block images in messages that SpamGuard thinks are spam.
Keeping the above in view there are a few steps that can help the marketers largely.
You can host a version of your message on the Web. Provide a text link to it at the very top of your message. Regardless of image or personal settings, the recipient can always click through and view the message as a Web page. Similarly, The preview pane is like a newspaper's "top of the line” area and is where many recipients read or scan their messages. The preview can have "open” option for decision based on content showing in the preview pane.
A strong text version ensures you still reach users, regardless of format preference. With HTML email so popular, text versions are being eliminated Yet recent email client changes mean users have an increased ability to select which default format they prefer. Similarly, some publishers report text ads deliver higher CTRs than image-based ads.
If your email includes several key linked images, consider adding text-based links above or below the image or appropriately placed in nearby copy. Although many email services and clients do not display alt tags when images are disabled, it is always a good idea to include them. This gives the viewer an idea of what he or she is not able to see.
There are some ISPs like AOL and other managed mail networks that can whitelist commercial mailers. This ensures selected email is allowed through with a minimum of filtering, including the blocking of images. In the business-to-consumer (B2C) environment, whitelisting usually happens at the user level. A user needs to add the sender's address to their address book. This way the ISPs do not interfere with the messages and leave even the images unblocked.