Summary
The hostname used for image hosting significantly affects email deliverability primarily through its impact on sender reputation. Sharing a domain with others, particularly if they engage in poor sending practices or are associated with spam, can harm your own deliverability. It is highly recommended to use dedicated domains or subdomains for image hosting to isolate your reputation and maintain control. Services like CloudFront can be beneficial, but utilizing dedicated hostnames within those services (e.g., CNAMEs) is critical. Proper DNS configuration and choosing reputable image hosting services also contribute to positive deliverability.
Key findings
- Hostname is Key: The hostname used for image hosting is a primary factor influencing email deliverability.
- Shared Reputation Risks: Sharing a hostname or domain for image hosting can expose you to the negative reputation of other users.
- Dedicated Resources Improve Deliverability: Using dedicated domains or subdomains for image hosting helps isolate reputation and improve deliverability.
- Poor Reputation Leads to Spam: Poor domain reputation due to image hosting practices can result in emails being marked as spam.
- DNS Configuration is Crucial: Correct DNS configuration for image hosting domains is vital for establishing trust and avoiding spam filters.
Key considerations
- Choose Dedicated Hostnames: Opt for dedicated hostnames (CNAMEs) for image hosting to control and isolate your reputation.
- Monitor Reputation Regularly: Monitor the reputation of your image hosting domain and take corrective action if issues arise.
- Configure DNS Properly: Ensure that DNS records for your image hosting domains are accurately configured.
- Select Reputable Services: Choose reputable image hosting services or CDNs to minimize the risk of association with spam or low-quality content.
- Understand Hostname Structure: Carefully consider the structure of your image hosting hostname (e.g., subdomain vs. shared domain) and its impact on deliverability.
What email marketers say
9 marketer opinions
The hostname used for image hosting significantly impacts email deliverability due to its effect on sender reputation. Sharing a domain with others, especially if they have poor sending practices or are associated with spam, can negatively affect your deliverability. Using a dedicated subdomain or a separate domain for image hosting is a recommended best practice to isolate your reputation and maintain control over deliverability.
Key opinions
- Sender Reputation: The domain used for image hosting contributes to your overall sender reputation, influencing whether emails reach the inbox or are flagged as spam.
- Shared Domains: Using a shared domain for image hosting can expose you to the negative impact of other users' sending practices.
- Dedicated Subdomains: Implementing a dedicated subdomain (e.g., images.yourdomain.com) helps isolate deliverability issues related to image hosting from the primary email sending domain.
- Blacklisting: If an image hosting domain is blacklisted for spam or abuse, emails containing images from that domain are more likely to be flagged as spam.
Key considerations
- Domain Choice: Carefully choose the domain or subdomain for image hosting to ensure it has a clean reputation and is not associated with spam or malicious content.
- Isolation: Isolate image hosting from your main email sending domain by using a dedicated subdomain or separate domain.
- Reputation Monitoring: Monitor the reputation of your image hosting domain to identify and address any issues that could negatively impact deliverability.
- Service Reputation: Consider the reputation of the image hosting service you use, as some shared hosting services may have issues with spam or abuse.
Marketer view
Email marketer from Mailjet shares that sender reputation is tied to the domain. If you use a shared domain for image hosting, your deliverability can be affected by the actions of other users. Using a subdomain or a dedicated domain for image hosting helps isolate your reputation.
4 Jun 2025 - Mailjet
Marketer view
Email marketer from Reddit recommends using a dedicated subdomain for image hosting (e.g., images.yourdomain.com) to isolate potential deliverability issues related to image hosting from your main email sending domain.
3 Jun 2022 - Reddit
What the experts say
6 expert opinions
The hostname used for image hosting is a crucial factor influencing email deliverability. It directly impacts sender reputation, as sharing hostnames with spammers or those with poor practices can damage your own. Using dedicated domains or subdomains for image hosting is recommended to isolate reputation and maintain control over deliverability. Services like CloudFront are similar to Akamai and built on S3.
Key opinions
- Hostname Importance: The hostname within the image URL is a primary determinant of email deliverability.
- Shared Reputation: Sharing a hostname, like 'cloudfront.com', means sharing reputation with all other users, which can be unpredictable.
- Dedicated Hostnames: Using a dedicated hostname, like 'yourbrand.cloudfront.com', isolates your reputation and reduces the risk of being affected by others.
- Spam Association: Hostnames associated with spam or malicious content can lead to email filtering or blocking, harming deliverability.
Key considerations
- Dedicated Resources: Consider using dedicated domains or subdomains to host images to isolate your sender reputation.
- Reputation Monitoring: Regularly monitor the reputation of your image hosting hostname to identify and address any potential issues.
- Service Selection: When choosing a CDN or image hosting service, select a reputable provider to minimize the risk of association with spam or low-quality content.
- Hostname Structure: Opt for a hostname structure that reflects your brand and distinguishes your content from generic shared resources.
Expert view
Expert from Email Geeks shares that Cloudfront is like Akamai and is built on top of S3.
10 Mar 2025 - Email Geeks
Expert view
Expert from Email Geeks explains that the main thing that affects deliverability is the hostname used in the URL.
1 Feb 2022 - Email Geeks
What the documentation says
4 technical articles
The hostname used for image hosting plays a critical role in email deliverability, primarily through its influence on domain reputation. Utilizing dedicated hostnames or CNAMEs for image hosting allows senders to control and isolate their reputation from other users. A positive domain reputation is essential for ensuring emails reach the inbox, while a poor reputation can result in emails being marked as spam. Proper DNS configuration for the image hosting domain is also vital for establishing trust and avoiding spam filters.
Key findings
- Domain Reputation Impact: The domain used for image hosting significantly influences overall domain reputation, which directly affects email deliverability.
- Dedicated Hostnames Benefit: Using dedicated hostnames (CNAMEs) for image hosting provides control over domain reputation and isolates image traffic.
- Spam Filtering: Poor domain reputation can lead to emails being marked as spam, reducing the likelihood of them reaching the intended recipient.
- DNS Configuration: Correct DNS configuration for the image hosting domain is crucial for establishing trust and avoiding spam filters.
Key considerations
- Implement Dedicated Hostnames: Implement dedicated hostnames (CNAMEs) for image hosting to manage and protect your sender reputation.
- Monitor Reputation: Regularly monitor the reputation of your image hosting domain and take steps to address any issues that may arise.
- DNS Configuration: Ensure that DNS records for your image hosting domain are correctly configured to build trust and avoid spam filters.
- Positive Reputation Maintenance: Prioritize maintaining a positive domain reputation by adhering to best practices for email sending and image hosting.
Technical article
Documentation from Microsoft explains that domain reputation affects email deliverability and is influenced by several factors, including the domain used for hosting images linked in emails. A poor reputation can lead to emails being marked as spam.
29 Aug 2022 - Microsoft
Technical article
Documentation from Google highlights the importance of maintaining a good sending reputation to ensure emails reach the inbox. This includes ensuring that any domains or subdomains used for image hosting have a positive reputation.
11 Nov 2024 - Google
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