Thin horizontal line appears between images during reading in the webtoon reader

What happened?

When reading webtoons in Kavita (in browser), thin horizontal lines appear between images.

Steps to reproduce:

1. Open the webtoon reader in Firefox (also reproducible in Chrome).
2. Scroll through the images — horizontal lines at random points.
3. Changing the Width Override value moves the position of the lines, but they still appear.

What did you expect?

The images should connect smoothly without any lines or gaps between them.

Kavita Version Number - If you don't see your version number listed, please update Kavita and see if your issue still persists.

0.8.8 - Stable

Are you accessing kavita through a reverse proxy? If yes, confirm that the issue persists with a direct connection

Yes

What operating system is Kavita being hosted from?

Docker (LSIO Container)

If the issue is being seen on Desktop, what OS are you running where you see the issue?

Windows

If the issue is being seen in the UI, what browsers are you seeing the problem on?

Firefox & Chrome

If the issue is being seen on Mobile, what OS are you running where you see the issue?

None

If the issue is being seen on the Mobile UI, what browsers are you seeing the problem on?

No response

Relevant log output

Additional Notes

• The color of the line matches the background color
• Changing the reader background color makes the lines change color as well.
• Happens on Firefox & Chrome