Adding new sites / changing themes - checkered background displays in card thumbnails because thumbnails are the wrong size

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: Master
• Fix Version/s: Master
• Component/s: Frontend Infrastructure
• Labels: None
• Fix Priority: 3
• Sprint: S02E12 - Donnie Darko
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/71568

Reproduced on:
Tomcat 9.0.10 + MySQL 5.7. Portal master GIT ID: 6e9ff2489f58b5620382ae1a3aba895f8701f43e.

Steps to reproduce:

1. Add a new site

• OR -

1. Add a widget or content page
2. Configure the page
3. Click the "Look and Feel" tab
4. Click "Define a specific look and feel for this page"
5. Change the theme

Expected result:
The thumbnails for the other theme take up the entire blank space of the card.

Actual result:
The thumbnails are the wrong size so the checkered background is shown.