It switches to the horizontal layout so it can show more than two channels. Reaper keeps the track's channel count the same even after you delete the plugins, so it's still sitting there with 8 channels or whatever.
Open the track's routing window (the "ROUTE" button in the default theme) and change Track Channels, at the top, back to 2.
Also, for pictures you usually want to use:
Code:
[img]https://imgur.com/I4TCVO8[/img]
When using the URL tag, which is a good idea for bigger images, you need a closing tag too:
Code:
[url=https://imgur.com/I4TCVO8]Example image 1[/url]