Stacked email images displaying with 1px gaps in-between (mobile)

Technical Q&A
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Topic summary

A user is experiencing 1-pixel gaps appearing between stacked full-width images in email campaigns when viewed on mobile devices, while desktop rendering shows no gaps.

Technical Details:

  • Issue occurs specifically on mobile (iPhone tested)
  • Tested in Gmail mobile and desktop apps
  • Attempted fixes include adjusting individual image background colors and email content background color, with no success

Context:

  • Images are being sliced and stacked for email campaigns
  • User acknowledges this approach (manually coding vs. using text) may not be best practice, but prefers it for speed and greater visual customization control

Status: The issue remains unresolved, and the user is seeking advice on how to eliminate these mobile rendering gaps.

Summarized with AI on November 6. AI used: claude-sonnet-4-5-20250929.
1

Hi all,

While creating campaigns in the email app, I’m having difficulty getting stacked, full-width images to render without gaps in-between on mobile. On desktop there are no 1px lines between images, but on mobile I haven’t been able to figure out how to get rid of them, despite changing individual images’ background colors or the entire email content background’s color.

For context, we’ve been slicing images that contain text vs manually coding these emails. I understand this isn’t best practice, but it’s fast and we’re able have more visual customization this way.

Screenshots were taken in Gmail desktop app and mobile app on iPhone.

Any advice is apprciated

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