Set the image size in markdown syntax

Controlling Image Size in Markdown

Standard Markdown syntax doesn’t include built-in parameters for image dimensions. The basic syntax ![alt text](image.url) produces images at their original size or constrained by container width, with no way to specify explicit dimensions.

If you need to control image size, you have several options depending on your use case and platform.

HTML <img> Tag

The most direct approach is using HTML directly within your Markdown document:

<img src="http://example.com/img.png" alt="img text" width="400" height="300" />

This works universally across Markdown processors and gives you full control. Specify dimensions in pixels, or use percentage values for responsive layouts:

<img src="http://example.com/img.png" alt="img text" width="80%" />

Markdown Extensions

Many Markdown flavors support extended syntax for sizing. Check what your platform uses:

Kramdown (Jekyll, GitHub Pages):

![alt text](image.png){:width="400px" height="300px"}

Pandoc:

![alt text](image.png){width=400 height=300}

MultiMarkdown:

![alt text][image]

[image]: http://example.com/img.png "title" {width=400px height=300px}

HTML with CSS Classes

For styling consistency across multiple images, use HTML with class attributes:

<img src="http://example.com/img.png" alt="img text" class="thumbnail" />

Then define in your CSS:

img.thumbnail {
    width: 200px;
    height: auto;
}

Picture Element for Responsive Images

If you’re building modern web content, use the HTML <picture> element for responsive images:

<picture>
    <source media="(min-width: 768px)" srcset="large-image.png">
    <source media="(min-width: 480px)" srcset="medium-image.png">
    <img src="small-image.png" alt="descriptive text" style="width: 100%; height: auto;">
</picture>

This approach loads different image sizes based on device width, improving performance and user experience.

Practical Considerations

• Aspect ratio: Use width and height attributes together, or set one dimension and use height: auto in CSS to maintain aspect ratio
• Responsive design: Avoid fixed pixel dimensions on fluid layouts; prefer percentage-based widths or CSS media queries
• Accessibility: Always include meaningful alt text regardless of which method you use
• Platform limitations: Check your Markdown processor’s documentation—not all support extensions equally

For static site generators like Jekyll or Hugo, check what Markdown library they use (kramdown, goldmark, etc.) to know which syntax extensions are available. For simple cases where you need one-off sizing, raw HTML remains the most portable solution.