Your link previews are blank because og:image is missing. Here is a stdlib-only Python fix

When you link your product, documentation or personal project to Slack, Discord, X or LinkedIn, the platform generates a preview card using your Open Graph tags. If the og:image tag is absent or points to a default image, the preview appears as a grey box or stock logo. This can negatively impact click-through rates, as users cannot see your actual content.

This article outlines three ways to address this issue: a quick check for missing og:image, an all-standard-library Python script to generate a 1280x720 cover image, and how to integrate the image into your webpage.

To verify if your page has an og:image, run this command: curl -s https://your-site.example/page | grep -io meta[^ ]*og:image[^ ]. Three possible outcomes: no output, indicating the absence of an og:image; a generic URL, such as your host's or storefront's logo; or a unique image specific to your page. Additionally, you can check og:title and og:description in the same manner.

To create a PNG image using only the Python standard library, refer to the following code snippet:

```python

import struct

import zlib

def _chunk(kind, data):

body = kind + data

return (struct.pack(I, len(data)) + body + struct.pack(I, zlib.crc32(body) & 0xFFFFFFFF))

def write_png(path, width, height, rows):

raw = b'\x00' + b''.join(rows)

ihdr = struct.pack(IIBBBBB, width, height, 8, 2, 0, 0, 0)

png = b'\x89PNG\r\n\x1a\n' + _chunk(b'IHDR', ihdr) + _chunk(b'IDAT', zlib.compress(raw, 9)) + _chunk(b'IEND', b'')

with open(path, 'wb') as f:

f.write(png)

```

Use this script to create a diagonal two-color gradient with a solid accent bar, which looks far more engaging than a grey box. The gradient can be customized by adjusting the color values for the colors, c1 and c2, and accent.