Banner image generation missing speaker images

[jetzlstorfer]

Seems that something broke the fetching of linkedin speaker images and now our generated banners don't show the speaker profile pictures anymore.

One way to fix is to download the picture (if available) so it doesn't break when regenerating the image.

[jetzlstorfer]

Needs to be fixed in this repo: https://github.com/CloudNativeLinz/go-image-generator