Why GitHub README Images Are Broken, Blurry, or Too Large
When a student or maintainer pushes a README update and the screenshot shows as a broken icon, the cause is usually simple: the image path does not resolve from the Markdown file, the file was moved, the branch changed, or the image was never stored somewhere visitors can reach. Other problems are less obvious: the screenshot loads but the text is unreadable, the diagram is too wide on mobile, or an animated GIF turns a short README into a slow preview.
This page is a diagnostic checklist for GitHub README image not showing issues, blurry documentation screenshots, oversized demos, and images that work locally but fail for everyone else.
Why the README image does not show
Start with the image location. GitHub can render images in Markdown files when the path or URL points to a reachable image. If you reference a local computer file such as C:/Users/..., visitors cannot load it. If you use a relative path, that path is resolved from the Markdown file location. Moving README.md into a docs folder changes what images/demo.png means.
Branch names also matter. A copied URL that points to master may fail after a repository moves to main. Case matters too: Dashboard.PNG and dashboard.png are not the same filename in many repository and deployment contexts.
Why screenshots look blurry
A screenshot can be technically valid and still fail the reader. Blurry README screenshots often come from resizing twice: first by exporting a large screenshot at a strange size, then by letting GitHub render it smaller in the README. JPG compression can also create visible artifacts around code, terminal text, thin UI borders, and diagram labels.
For UI screenshots, prefer a cropped PNG delivery copy. Keep the source capture separately, but commit a version sized for the README preview. A dashboard screenshot that will appear around 800 pixels wide does not need to be a full desktop capture with two empty sidebars and browser tabs.
Why diagrams become unreadable on mobile
Architecture diagrams fail when they try to explain too many relationships at once. In a wide GitHub README preview, a six-column diagram might look fine. On a phone-width preview, the same diagram becomes a stripe of tiny labels. Split complex diagrams into smaller documentation figures: one for setup, one for runtime flow, one for deployment, and one for data ownership if needed.
Why GIF demos make a README heavy
Animated GIFs are useful for short interactions, but they can become much larger than a static screenshot. A long full-screen GIF repeats pixels across many frames, distracts from the setup steps, and may make a repository feel unpolished. Use short, cropped GIFs only when motion explains something a static image cannot. Otherwise, use a still screenshot with a clear caption.
Diagnostic checklist
| Question | What to check | Likely fix |
|---|---|---|
| Is the image stored in the repository or reliably hosted? | A visitor must be able to reach the file without your local machine. | Commit it under docs/images, assets, or another documented folder. |
| Is the relative path correct from the Markdown file? | Paths are relative to the file containing the Markdown. | Use ./, ../, or a root-relative repository path intentionally. |
| Did the branch or folder name change? | Old copied URLs often point to a previous branch or location. | Prefer a current relative path for repo-stored images. |
| Is the file name case correct? | Uppercase and lowercase differences can break image references. | Match the exact filename and extension. |
| Is the image readable at GitHub preview size? | UI labels, code text, and diagram nodes must remain legible. | Crop clutter, export PNG for text-heavy images, and avoid over-compression. |
| Did you remove private data? | Look for tokens, emails, internal URLs, customer data, and private repo names. | Redact the source copy before creating the delivery image. |
When the image works locally but not on GitHub
Local Markdown preview tools can be forgiving because they can read files from your computer. GitHub visitors only see what exists in the repository or at a reachable URL. If your editor preview loads ../../Desktop/mockup.png, that is not proof the public README will work. Commit the image into a stable repository folder and preview the rendered README on GitHub itself.
FAQs
The most common causes are a wrong relative path, a moved image folder, a renamed branch, filename case mismatch, a local file path, or a URL copied from a place that visitors cannot access.
It may have been exported too small, compressed too aggressively, saved as JPG even though it contains text, or displayed at a different size than expected. Re-crop from the source and use PNG for text-heavy visuals.
Yes. Screenshots can reveal API tokens, emails, internal URLs, private repository names, customer data, dashboards, and terminal paths. Review the source screenshot before optimization and commit only the redacted delivery copy.
