CDN URL Patterns, Versioning, and Embedding Best Practices

Every file in the tutosrive/images-projects-srm-trg repository is automatically served as a CDN asset through jsDelivr. Understanding the two URL formats — branch-pinned and commit-pinned — is the key to using these assets reliably in development workflows, public READMEs, and long-lived documentation. This page covers URL construction, caching semantics, how to locate commit SHAs, and practical embedding examples across the most common file types and environments.

The Two URL Formats

All Dev Forge CDN URLs share the same base structure. The only part that varies is the <ref> segment — the Git reference that determines which version of the file jsDelivr serves.

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@<ref>/<path-to-file>

Format 1 — Branch URL (`@main`)

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/<path-to-file>

This URL resolves to whatever version of the file currently exists on the main branch. It is convenient during active development because you always get the most recent asset without updating the URL. The trade-off is that jsDelivr caches @main responses for approximately 7 days, so a newly committed file or an updated asset may not appear immediately at the CDN edge. Example — Dev Forge logo (WebP):

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/dev2forge/dev2forge-logo.webp

Example — NBAI logo (PNG):

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/NBAI/logo.png

Example — ChromoLog logo (WebP):

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/modules/chromalog_logo.webp

Format 2 — Pinned Commit SHA (`@<commit-sha>`)

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@<commit-sha>/<path-to-file>

Replacing <ref> with a full 40-character Git commit SHA creates an immutable URL. Because the SHA uniquely identifies a single point in the repository’s history, the file at that URL can never change. jsDelivr recognises pinned-SHA URLs and caches them indefinitely at every edge node, resulting in the fastest possible load times and eliminating any risk of an unexpected asset change. Example — InitVenv tag preview (PNG), pinned to commit db610fff:

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@db610fff56de446492611132cc5dc85b3cade010/dev2forge/InitVenv/initvenv-tag-preview.png

Example — InitVenv icon (ICO), pinned to commit dd775fc2:

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@dd775fc24cf6c63171b85694bd0b7d567f055676/dev2forge/InitVenv/icon.ico

Example — InitVenv explorer screenshot (PNG), pinned to commit 591ea68b:

https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@591ea68b0a5c28922df1cc9471fba52746db48e1/dev2forge/InitVenv/initvenv-explain-explorer1.png

Format Comparison

	`@main` (branch)	`@<commit-sha>` (pinned)
Resolves to	Latest file on `main`	Exact file at that commit
URL changes needed on update	Never	Yes — new SHA per update
jsDelivr cache lifetime	~7 days	Indefinite
Stability	May change if `main` is updated	Immutable — never changes
Performance	Good	Best (fully edge-cached)
Recommended use	Local development, staging, drafts	Production READMEs, release docs, published sites

Always use a pinned commit SHA URL in any publicly released artifact — a GitHub README, a published docs page, a blog post, or a release changelog. The indefinite edge caching gives users the fastest possible load time, and you are guaranteed the asset will never silently change.

How to Get a Commit SHA

You need a commit SHA only when creating pinned URLs. There are two easy ways to find one.

From the GitHub UI

Navigate to the file in the repository on github.com/tutosrive/images-projects-srm-trg.
Click the History button (top-right of the file view) to see commits that touched the file.
Click any commit entry to open the commit detail page.
Copy the full SHA from the URL bar (e.g. db610fff56de446492611132cc5dc85b3cade010) or from the commit header on the page.

From the Command Line

# Show the last 10 commits with their full SHAs
git log --oneline -10

# Show the SHA of the commit that last modified a specific file
git log -1 --format="%H" -- dev2forge/InitVenv/InitVenv-logo.svg

Paste the resulting 40-character SHA directly into the URL template, replacing <commit-sha>.

Usage in Different Contexts

The same CDN URL works in any environment that can render a remote image over HTTPS. The examples below use real asset paths from the repository.

Markdown README Badges

Markdown is the most common context for Dev Forge CDN assets. Drop the URL into standard image syntax:

<!-- InitVenv SVG logo — latest -->
![InitVenv Logo](https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/dev2forge/InitVenv/InitVenv-logo.svg)

<!-- ChromoLog logo — latest -->
![ChromoLog Logo](https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/modules/chromalog_logo.webp)

<!-- NBAI logo — latest -->
![NBAI Logo](https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/NBAI/logo.png)

<!-- Clickable logo linking to the project site -->
[![InitVenv](https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/dev2forge/InitVenv/InitVenv-logo.svg)](https://dev2forge.software/initvenv/)

HTML `<img>` Tags

Use the CDN URL as the src attribute of any <img> element. Add width, height, and alt for accessibility and layout stability:

<!-- SVG logo — scales to any size without pixelation -->
<img
  src="https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/dev2forge/InitVenv/InitVenv-logo.svg"
  alt="InitVenv Logo"
  width="160"
  height="160"
/>

<!-- Animated GIF demo (ChromoLog usage example) -->
<img
  src="https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/modules/chromolog.gif"
  alt="ChromoLog usage demonstration"
  width="700"
/>

<!-- NBAI Gemini prompt test GIF -->
<img
  src="https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/NBAI/testing-gemini-prompt.gif"
  alt="NBAI Gemini prompt test"
  width="700"
/>

CSS `background-image`

CDN URLs work directly in CSS for decorative backgrounds:

/* Hero section with Dev Forge thumbnail as background */
.hero {
  background-image: url(
    "https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/dev2forge/thumbanil-dev2forge.png"
  );
  background-size: cover;
  background-position: center;
}

/* Card with ChromoLog logo as a centred background icon */
.chromolog-card {
  background-image: url(
    "https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/modules/chromalog_logo.webp"
  );
  background-repeat: no-repeat;
  background-position: center;
  background-size: contain;
}

Python Docstrings and Sphinx Docs

Sphinx’s .. image:: directive accepts remote HTTPS URLs, making CDN assets easy to embed in API reference documentation:

def configure_logging(level: str = "INFO") -> None:
    """
    Configure the ChromoLog colorised logging handler.

    .. image:: https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/modules/chromalog_logo.webp
       :alt: ChromoLog Logo
       :width: 120px
       :align: left

    Parameters
    ----------
    level : str
        Logging level string — one of ``DEBUG``, ``INFO``, ``WARNING``,
        ``ERROR``, or ``CRITICAL``. Defaults to ``INFO``.
    """
    ...

For RST-only Sphinx projects, the same directive works in any .rst file:

.. image:: https://cdn.jsdelivr.net/gh/tutosrive/images-projects-srm-trg@main/NBAI/logo.png
   :alt: NBAI Logo
   :width: 200px

Cache Behaviour

Ref type	Cache lifetime	Purge possible?
`@main` (branch)	~7 days	Yes, via jsDelivr purge tool
`@<commit-sha>` (pinned)	Indefinite	Not required — content is immutable

jsDelivr automatically caches responses at its global network of edge nodes. For branch URLs, the cache is refreshed approximately every 7 days, or you can manually trigger a purge through the jsDelivr purge tool if you need an update to appear sooner. Pinned-SHA URLs never need purging because the content they point to cannot change.

Rate Limits and Cost

jsDelivr is completely free for open-source projects. There is no API key, no registration, and no usage quota for files served from public GitHub repositories. The tutosrive/images-projects-srm-trg repository already tracks its own CDN hit count via the jsDelivr stats badge embedded in the project README:

![jsDelivr hits](https://img.shields.io/jsdelivr/gh/hy/tutosrive/images-projects-srm-trg)

Only use CDN URLs that point to tutosrive/images-projects-srm-trg. Do not hotlink images from unrelated or unknown third-party GitHub repositories — you have no control over their content, and those files can be changed or deleted at any time without notice. All Dev Forge assets in this repository are versioned, catalogued, and maintained specifically for stable CDN delivery.

Production checklist before publishing a README or docs page:

Replace every @main URL with a pinned @<commit-sha> URL.
Verify each URL returns a 200 OK by opening it in a browser.
Confirm alt text is set on every <img> tag for accessibility.
For SVGs, prefer the .svg format over .webp or .png — SVGs are resolution-independent and typically far smaller in file size.

Get Started

Asset Catalog

CDN URL Patterns, Versioning, and Embedding Best Practices

The Two URL Formats

Format 1 — Branch URL (`@main`)

Format 2 — Pinned Commit SHA (`@<commit-sha>`)

Format Comparison

How to Get a Commit SHA

From the GitHub UI

From the Command Line

Usage in Different Contexts

Markdown README Badges

HTML `<img>` Tags

CSS `background-image`

Python Docstrings and Sphinx Docs

Cache Behaviour

Rate Limits and Cost

Build docs developers (and LLMs) love

Get Started

Asset Catalog

Documentation Index

​The Two URL Formats

​Format 1 — Branch URL (@main)

​Format 2 — Pinned Commit SHA (@<commit-sha>)

​Format Comparison

​How to Get a Commit SHA

​From the GitHub UI

​From the Command Line

​Usage in Different Contexts

​Markdown README Badges

​HTML <img> Tags

​CSS background-image

​Python Docstrings and Sphinx Docs

​Cache Behaviour

​Rate Limits and Cost

Build docs developers (and LLMs) love

The Two URL Formats

Format 1 — Branch URL (`@main`)

Format 2 — Pinned Commit SHA (`@<commit-sha>`)

Format Comparison

How to Get a Commit SHA

From the GitHub UI

From the Command Line

Usage in Different Contexts

Markdown README Badges

HTML `<img>` Tags

CSS `background-image`

Python Docstrings and Sphinx Docs

Cache Behaviour

Rate Limits and Cost