Apple uses the term Retina display to describe high-DPI screens where individual pixels are no longer visible to the human eye.
While “Retina” is an Apple trademark, the term is commonly used to describe high-DPI displays across all devices—and images optimized for them.
Short answer
Retina images in email signatures ensure sharp visuals on high-DPI screens. Use images at 2× their display size and scale them down in HTML to prevent blurry or pixelated logos.
Do you need retina images?
Visuals are often the first thing people notice in an email. Before reading text or clicking links, users focus on design and imagery.
If your images are not optimized for high-DPI screens, they can appear blurry or pixelated, which may negatively impact how your brand is perceived.
How to use retina images in an email signature
High-DPI displays typically have about twice the pixel density of standard screens.
To ensure sharp images, upload graphics at 2× the intended display size, then scale them down using HTML.
Example:
If your logo should display at 100 × 29 pixels, uploading it at that exact size may result in a blurry image on retina screens:
<img alt="Xink" src="xink_logo_100_29.png" width="100" height="29" style="display:block;border:0;">
Instead, upload a larger version (e.g. 200 × 58 pixels) to maintain sharpness:
Then scale it down in your HTML:
<img alt="Xink" src="xink_logo_200_58.png" width="100" height="29" style="display:block;border:0;">
Things to consider
Using larger images improves quality but also increases file size, which can slow down email loading—especially on mobile devices.
To keep performance high, always compress your images before uploading.
Popular image optimization tools:
ImageOptim, JPEGmini, TinyPNG, Compressor.io, Kraken
AI-powered image optimization tools:
Let’s Enhance, Upscale.media, Pixelcut, Adobe Firefly
AI tools can automatically enhance sharpness, upscale images, and reduce file size while maintaining visual quality.
Most tools allow you to drag and drop images for quick optimization before adding them to your email signature.
