If overzealous ISP and corporate spam filters don’t cause enough stress for permission-based email marketers, now we must deal with blocked images almost universally. In email clients that block images by default, such as Outlook 2003, a recipient can read an entire column (such as this one) either in the message preview pane or when it’s opened. The image-based ads and our dashing photo won’t appear (nor will the message be counted as opened). For publishers, advertisers, and e-tailers, this isn’t just a nuisance. It’s potentially costly.
The Blocked Images Issue
An estimated 95 percent of all commercial email messages are sent in HTML or in a multipart (combined HTML and text) format. Most email includes at least a single external image, even if it’s the open-tracking image, a clear, one-pixel GIF image used to track whether an email has been opened.
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 pornographic images from loading and to prevent spammers from knowing if users open their messages. Gmail, for example, states: "Gmail disables images sent to you to protect you from unknown senders, like spammers, who use images and links to verify that your email address is real."
The latest versions of many major ISPs’ email interfaces and email clients automatically block any external image (see table at the end of the column). In addition to Gmail, Microsoft’s recent Windows XP Service Pack 2 upgrade adds the blocked images feature to its Outlook Express client.
Implications for Permission Marketers
Disabled images have big implications for marketers, including:
What Can Marketers Do?
A few steps marketers can take to help minimize the issue:
Blocked images should only be a minor nuisance for most permission email marketers who follow best practices and provide real value to recipients. Deliver the best, most relevant, personalized content to subscribers, and most will want to view your entire email with images, not just the text.
Till next time, keep on deliverin’.
|Image Blocking by Major ISPs & E-mail Clients|
|Blocking Issue||AOL |
|External images are blocked by default||Yes||Yes||No||No||No||Yes||Yes||No|
|User controls image-blocking settings||Yes||No||Yes||Yes||Yes||Yes||Yes||Yes|
|User clicks link to enable message’s images||Yes||Yes||Yes||No||No||Yes||Yes||N/A|
|Images enabled if sender is in user’s address book/buddy list||Yes||No||Yes||No||Yes||Yes||Yes||Yes|
|Images autoenabled if sender is on ISP whitelist||Yes||N/A||Yes||No||N/A||N/A||N/A||N/A|
|Alt tags displayed when images disabled||No||Yes||No||No||No||No||No||N/A|
|Preview window featured included||No||No||No||No||Yes||Yes||Yes||Yes|
|Note: SP2 = Service Pack 2 upgrade for Windows XP|
|Source: EmailLabs, 2004|
Want more email marketing information? ClickZ E-Mail Reference is an archive of all our email columns, organized by topic.
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As director of ISP relations and delivery, Kirill Popov creates and enforces strict usage and anti-spam policies, maintains ISP and community relations, and oversees all abuse and policy investigations and inquiries for EmailLabs clients. Kirill works with clients on best practices, content, design, and list hygiene to minimize potential delivery issues. He's a registered member of the SpamCon foundation and representsEmailLabs on AIM's Council for Responsible E-Mail.
Loren McDonald is vice president of marketing at e-mail marketing automation company EmailLabs, overseeing corporate marketing activities and client consulting services. He has 20 years experience in marketing, consulting and strategic planning. Earlier, Loren was founder and president of Intevation, an e-marketing services firm specializing in e-mail and SEM. He's held executive marketing positions at companies including USWeb/CKS (marchFIRST), NetStruxr, and Arthur Andersen.
December 12, 2013
1:00pm ET / 10:00am PT