Documentation screenshots not loading

[espiegelberg]

Describe the bug
When visiting https://pub.dev/packages/platform_maps_flutter, the four example screen shots are not appearing.

When manually following the links to each image, the following error is returned: "Error Fetching Resource".

To Reproduce
Steps to reproduce the behavior:

1. Go to https://pub.dev/packages/platform_maps_flutter
2. Scroll down to 'Screenshots'
3. See error that all four images failed to load

Expected behavior
The screenshots should be visible.