[Issue]: Extra network tab issues

[Erehr]

What happened?

Two issues after recent update.

1. Lazy loading model previews is just bad. The images are not cached so whenever you switch tab, search or even scroll the images are unloaded (even while still in view as in image below, if 1px is out of view the image dissapear). Switching tabs for example each time it takes even few seconds for all previews to load again and again unnecessary.
   

Images not caching seems to by caused by timestamp added to preview img src
&mtime=${new Date().getTime()}}`

2. Setting "Card height for Extra Networks (in pixels)" is not working anymore.

Checklist

• I have searched the issues to make sure this is not a duplicate
• Webui is up to date
• Cozy-Nest is up to date
• All my extensions are up to date