How can I improve email deliverability for large emails with many images and links when experiencing high spam complaint rates?

Summary

Improving email deliverability for large emails with many images and links, particularly when experiencing high spam complaint rates, requires a holistic approach. While email size and link count are not primary drivers of deliverability issues, focusing on sender reputation is crucial. This involves implementing and maintaining email authentication (SPF, DKIM, DMARC), diligently managing subscriber lists with clear opt-in processes and easy unsubscribe options, segmenting lists to target engaged subscribers, and using feedback loops to address spam complaints. Monitoring sender reputation, adhering to bulk sender guidelines from ISPs like Google and Microsoft, optimizing email content for different devices, and utilizing a reputable ESP are also vital. Employing dedicated IPs for high-volume sending and regularly validating email lists further enhance deliverability.

Key findings

  • Size & Links: Email size and the number of links are not direct causes of deliverability issues.
  • Authentication: Proper email authentication (SPF, DKIM, DMARC) is fundamental for verifying sender identity and improving deliverability.
  • List Management: Employing clear opt-in processes, honoring unsubscribe requests, and regularly cleaning lists improves engagement and deliverability.
  • Segmentation: Segmenting lists to target engaged subscribers reduces spam complaints and improves deliverability.
  • Feedback Loops: Using feedback loops from ISPs provides valuable data about spam complaints and deliverability issues.
  • Reputation Monitoring: Actively monitoring sender reputation helps identify and address issues affecting deliverability.
  • ISPs Guidelines: Adhering to bulk sender guidelines from major ISPs like Google and Microsoft is critical.
  • Content Optimization: Optimizing email content for different devices and using concise language improves engagement.
  • Dedicated IPs: Using a dedicated IP address can isolate sender reputation and enhance deliverability for high-volume senders.

Key considerations

  • Authentication Configuration: Ensure correct and consistent implementation of SPF, DKIM, and DMARC.
  • Opt-In & Unsubscribe: Establish clear opt-in procedures and easy-to-find unsubscribe links.
  • List Segmentation Strategy: Develop a strategy to segment email lists based on engagement and behavior.
  • Feedback Loop Setup: Sign up for and actively monitor feedback loops with major ISPs.
  • Reputation Tooling: Utilize reputation monitoring tools and regularly check sender scores.
  • ISP Compliance: Familiarize yourself with and adhere to the specific guidelines of ISPs like Google and Microsoft.
  • Content Optimization Plan: Create a plan to optimize email content for various devices and improve engagement.
  • Dedicated IP Evaluation: Assess the need for a dedicated IP based on sending volume and reputation.

What email marketers say
9Marketer opinions

To improve email deliverability for large emails with many images and links when experiencing high spam complaint rates, a multi-faceted approach is needed. This includes segmenting email lists to target engaged subscribers, improving sender reputation through authentication (SPF, DKIM, DMARC) and consistent sending volume, optimizing email content (image sizes, concise language, mobile-friendliness), regular list cleaning, creating engaging content, checking sender scores, running inbox placement tests, and potentially using a dedicated IP address.

Key opinions

  • Segmentation: Segmenting email lists and targeting engaged subscribers can improve deliverability and reduce spam complaints.
  • Sender Reputation: Improving sender reputation through authentication (SPF, DKIM, DMARC), consistent sending volume, and avoiding sudden spikes is crucial.
  • Content Optimization: Optimizing email content by reducing image sizes, using concise language, and ensuring mobile-friendliness can prevent triggering spam filters.
  • List Cleaning: Regularly cleaning email lists with email validation tools to remove unengaged subscribers improves sender reputation and deliverability.
  • Engaging Content: Creating engaging and valuable content for subscribers helps maintain a positive sender reputation.
  • Dedicated IP: Using a dedicated IP address for high-volume sending can isolate sender reputation and improve deliverability.

Key considerations

  • Segmentation Strategy: Determine how to effectively segment email lists based on engagement and implement a sunset policy for inactive contacts.
  • Authentication Setup: Implement and maintain SPF, DKIM, and DMARC authentication protocols to verify sender identity.
  • Content Optimization Techniques: Identify and implement strategies to optimize email content, including image compression, concise language, and mobile-friendly design.
  • List Cleaning Process: Establish a regular process for cleaning email lists using email validation tools and removing unengaged subscribers.
  • Monitoring Tools: Utilize sender score monitoring tools and inbox placement tests to identify and address deliverability issues.
  • ESP Reputation: Select a reputable ESP and check sender scores regularly
Marketer view

Email marketer from Stack Overflow suggests using a dedicated IP address for sending emails if you're sending a high volume of emails to isolate your reputation from other senders, which could be influencing your deliverability rates.

July 2022 - Stack Overflow
Marketer view

Email marketer from Email on Acid shares that optimizing your email for different devices, including using a responsive design and optimizing images, will reduce load times and improve engagement. They also suggest A/B testing different versions of your email.

May 2022 - Email on Acid
Marketer view

Email marketer from HubSpot recommends optimizing email content, including reducing image sizes and using concise language, to prevent triggering spam filters. They also recommend optimizing for mobile and using preheader text.

February 2024 - HubSpot
Marketer view

Email marketer from GlockApps emphasizes using a reputable email marketing service provider (ESP) and regularly checking your sender score. They also explain running inbox placement tests to identify and resolve deliverability issues.

July 2024 - GlockApps
Marketer view

Email marketer from Mailjet shares that segmenting your email list based on engagement can significantly improve deliverability. They suggest targeting engaged subscribers with larger emails and using a sunset policy to remove inactive contacts, reducing spam complaints.

March 2022 - Mailjet
Marketer view

Email marketer from ZeroBounce shares that cleaning email lists with email validation tools will reduce bounce rates and improve sender reputation, leading to better deliverability.

January 2025 - ZeroBounce
Marketer view

Email marketer from Reddit mentions focusing on sender reputation by ensuring consistent sending volume, proper authentication (SPF, DKIM, DMARC), and actively removing unengaged subscribers.

August 2021 - Reddit
Marketer view

Email marketer from Sendinblue advises focusing on improving sender reputation by authenticating your email with SPF, DKIM, and DMARC. They also stress the importance of consistent sending volume and avoiding sudden spikes, and cleaning your list regularly.

March 2024 - Sendinblue
Marketer view

Email marketer from Litmus responds that creating engaging content is key. They recommend testing rendering across different email clients and devices and providing clear value to subscribers.

July 2021 - Litmus

What the experts say
7Expert opinions

Improving email deliverability, particularly for large emails with numerous images and links experiencing high spam complaint rates, involves addressing several factors beyond just the email size and number of links. Key strategies include focusing on sender reputation through proper authentication (SPF, DKIM, DMARC) and monitoring, proactively managing subscriber lists by clarifying the source of addresses and ensuring affirmative opt-in, offering easy unsubscribe options, segmenting and restricting blasts to engaged subscribers only, and utilizing feedback loops to understand and address spam complaints. Analyzing sender reputation and using reputation monitoring tools are important.

Key opinions

  • Email Size & Links: Email size and number of links are not primary factors affecting deliverability.
  • Authentication: Proper implementation and maintenance of email authentication protocols (SPF, DKIM, DMARC) is essential.
  • List Management: Clarifying address sources and ensuring affirmative opt-in are crucial for list hygiene.
  • Unsubscribe Process: Making the unsubscribe option easily accessible can reduce spam complaints.
  • Engagement: Restricting email blasts to engaged subscribers improves deliverability.
  • Feedback Loops: Using feedback loops with ISPs provides data about spam complaints.
  • Reputation Monitoring: Monitoring sender reputation is vital and can be done using various tools.

Key considerations

  • Authentication Implementation: Ensure SPF, DKIM, and DMARC are correctly configured and maintained.
  • Opt-In Process: Implement a clear and affirmative opt-in process for subscribers.
  • Unsubscribe Placement: Move the unsubscribe link to a prominent position in emails.
  • Segmentation Strategy: Develop a strategy to segment and target engaged subscribers.
  • FBL Setup: Sign up for feedback loops with major ISPs.
  • Reputation Monitoring: Utilize reputation monitoring tools to track sender reputation metrics.
Expert view

Expert from Email Geeks suggests restricting the big blasts to engaged subscribers due to potentially unclear opt-in and/or hanging on to subscribers forever.

December 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that size is not a deliverability issue in general and remote images are not going to affect anything.

June 2021 - Email Geeks
Expert view

Expert from Email Geeks recommends moving the unsubscribe to the top so folks can actually unsubscribe rather than report as spam, clarifying the source of the addresses and only sending mail to people who have affirmatively opted in.

July 2022 - Email Geeks
Expert view

Expert from Word to the Wise (Dennis Dayman) answers that properly implementing and maintaining email authentication protocols (SPF, DKIM, and DMARC) is essential. He shares these help ISPs verify the sender's identity and improves deliverability and also shares monitoring authentication via services like dmarcian or easyDMARC.

October 2022 - Word to the Wise
Expert view

Expert from Word to the Wise (Laura Atkins) explains that monitoring your sender reputation is crucial. She explains senders should identify and address issues affecting their reputation, such as high complaint rates or being listed on blocklists. They also recommends looking into Return Path reputation monitoring.

February 2023 - Word to the Wise
Expert view

Expert from Spam Resource (John Levine) responds that signing up for feedback loops (FBLs) with major ISPs will provide valuable data about spam complaints, allowing you to identify and address issues causing those complaints.

July 2021 - Spam Resource
Expert view

Expert from Email Geeks shares that the number of links in an email isn't going to make your mail go to bulk if they are using only one domain.

October 2024 - Email Geeks

What the documentation says
4Technical articles

Improving email deliverability when facing low engagement and high spam rates, particularly with large emails containing numerous images and links, requires adherence to bulk sender guidelines, robust email authentication, and proactive list management. Google and Microsoft emphasize monitoring sender reputation through their respective tools (Postmaster Tools and JMRP) and ensuring valuable content. Authentication using SPF, DKIM, and DMARC is crucial for verifying sending identity, with the RFC providing technical specifications for SPF configuration.

Key findings

  • Sender Guidelines: Adhering to bulk sender guidelines from major ISPs like Google and Microsoft is essential for deliverability.
  • Authentication: Email authentication protocols (SPF, DKIM, DMARC) are critical for verifying sender identity and improving deliverability.
  • List Management: Maintaining clean email lists by honoring unsubscribe requests and providing valuable content is necessary.
  • Reputation Monitoring: Monitoring sender reputation using tools like Google Postmaster Tools and Microsoft JMRP is recommended.

Key considerations

  • Guideline Compliance: Review and adhere to the specific bulk sender guidelines provided by major ISPs like Google and Microsoft.
  • Authentication Implementation: Implement SPF, DKIM, and DMARC correctly, referencing technical specifications like the RFC for SPF records.
  • List Hygiene Practices: Establish processes for cleaning and maintaining email lists, including honoring unsubscribe requests.
  • Monitoring Tool Setup: Set up and regularly monitor sender reputation using Google Postmaster Tools and Microsoft JMRP.
Technical article

Documentation from Google Support explains that senders experiencing low engagement and high spam rates should review their sending practices against Google's bulk sender guidelines, focusing on authentication, list management, and content quality. Google also recommends using Postmaster Tools to monitor your sending reputation.

March 2025 - Google Support
Technical article

Documentation from RFC explains the technical specifications of Sender Policy Framework (SPF) records, including syntax, mechanisms, and qualifiers. This is crucial for understanding how to properly configure SPF for email authentication.

March 2022 - RFC
Technical article

Documentation from Microsoft explains that to ensure deliverability to Outlook.com inboxes, senders should monitor complaint rates through the Junk Email Reporting Program (JMRP). Furthermore, they recommend authenticating email, maintaining clean lists by honoring unsubscribe requests, and providing valuable content.

April 2021 - Microsoft
Technical article

Documentation from SparkPost explains the importance of email authentication protocols (SPF, DKIM, DMARC) to verify your sending identity and improve deliverability. They provide guides on implementing each protocol correctly.

September 2022 - SparkPost