HubSpot Email Image Sizes and Optimisation Guide

Start with the actual HubSpot email module width

A HubSpot marketing email can contain full-width image modules, smaller brand headers, multi-column sections and custom template components. Each placement has a different usable width, especially after padding and column spacing are applied.

Use the width of the image's visible container as the starting point. A 600px full-width section is a useful example, but HubSpot supports different template structures and does not establish 600px as a mandatory platform-wide image size.

Adjust every example to match the real email module. A padded image container can be narrower than the overall email frame.

Prepare HubSpot hero banners, content images and brand logos

A newsletter hero usually benefits from a predictable aspect ratio and clear central composition. Product images often work better as consistent square or portrait crops, while brand logos need sufficient surrounding space and crisp edges.

Keep essential campaign messages available as live text where possible. This improves accessibility and prevents small promotional lettering from disappearing on mobile.

Use HubSpot desktop and mobile visibility controls appropriately

HubSpot documents options for hiding specific sections on desktop or mobile and adjusting column configurations in the drag-and-drop marketing email editor. It also notes that emails built with design-manager templates may require developers to add device-specific behaviour manually.

This distinction matters when deciding whether to produce one adaptable hero image or separate desktop and mobile versions. A campaign cannot use a dedicated mobile image unless the chosen template actually supports that presentation.

• Review how columns stack when the email is viewed on a narrow screen.
• Check whether text inside an image remains readable after scaling.
• Verify that mobile-hidden and desktop-hidden sections display as intended.
• Inspect image padding so a full-width banner does not look cramped.
• Account for email clients that do not fully support mobile-specific behaviour.

Prepare sharper 2x assets without making the email wider

Retina preparation is based on the relationship between the source pixels and the visible image size. A 1200px image can supply extra detail for a banner shown at 600px, while a 720px image can support a 360px mobile-specific placement.

The image should continue to display at its intended module width. Avoid uploading an oversized source with no appropriate width control, and compare the final file weight against the improvement that users can actually see.

Read our Retina Email Images Guide for additional 1x, 1.5x and 2x examples.

Choose the appropriate format and reduce campaign image weight

JPG is often the practical choice for photographs, event banners and lifestyle imagery. PNG can work better for transparent logos, sharp diagrams or artwork with clear geometric edges. The best option depends on the visual content and final output, not simply the platform name.

Review the combined image weight of the entire message. A single well-optimised hero can still be followed by a heavy collection of product tiles, partner logos and footer graphics.

• Crop unused background before generating the campaign image.
• Export at the required display dimensions or selected density.
• Check smooth gradients, facial detail and small text after compression.
• Avoid converting transparent artwork to JPG when transparency is needed.
• Keep a clean source file so repeated edits do not accumulate compression artifacts.

The Email Image Size Guide explains practical file-size tradeoffs across different email layouts.

Check alternative text, dark backgrounds and preview text

HubSpot allows images to be given descriptive alternative text. Use that field to explain meaningful artwork, especially when an email client blocks images or the campaign is read with assistive technology.

HubSpot's mobile guidance also notes that alt text from images near the beginning of a message can influence email preview text. This should prompt careful testing, not an automatic removal of useful accessibility information.

Review transparent logos against light and dark backgrounds. If the visual disappears in dark mode, consider a suitable outline, a version designed for the background or a solid supporting shape where it fits the brand.

Test HubSpot email images across clients and devices

HubSpot provides marketing email previews for specific email clients and devices where the account supports them. Its documentation notes that available test volumes depend on the account's subscription, so check the current limits before planning a large QA cycle.

1. Check the actual image-module width and approved campaign dimensions.
2. Review desktop and mobile layouts in the email editor.
3. Inspect visibility settings, column stacking and image padding.
4. Confirm alternative text, links and relevant tracking parameters.
5. Use available client previews to examine Outlook, Gmail and other important inboxes.
6. Send real test emails to confirm image quality, preview text and final rendering.
7. Review important campaign assets against light and dark surfaces.

For another builder-based approach, compare the Mailchimp email image sizes guide.

Common HubSpot marketing email image mistakes

• Assuming that every HubSpot template must use a 600px-wide image.
• Ignoring module padding and creating a banner wider than its visible content area.
• Depending on mobile visibility features that the chosen template does not support.
• Uploading a large photographic source and assuming visible resizing reduces download weight.
• Removing useful alt text without first reviewing the accessibility consequences.
• Treating an editor preview as equivalent to testing a real Outlook or Gmail inbox.

Frequently asked questions about HubSpot email images

Official HubSpot email and image documentation

• HubSpot guidance for optimising marketing emails on mobile devices
• HubSpot email-client and device preview documentation
• HubSpot image sizing, links and alternative text

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