## Issue
6301: don't use CDN for GIF thumbnails
## Note
Just a minor mistake in the recent thumbnail refactoring; left out the handling when `allowGif` is true.
1. Lock the width of the second pane so that the layout doesn't shift after the image is fetched.
2. The image is huge, so pass through the optimizer.
- Wait until the container is mounted to get the exact image width.
Unfortunately, it still takes 0.8s on average to fetch the image, regardless of how small the image has been optimized.
Login graphic improvements
1. Lock the width of the second pane so that the layout doesn't shift after the image is fetched.
2. The image is huge, so pass through the optimizer.
- Wait until the container is mounted to get the exact image width.
Unfortunately, it still takes 1s (on average) to fetch the image, regardless of how small the image has been optimized.
