To recreate, just use a lasso tool in PS and the feather the selection (or not if you want a hard line.
After you have your layer masked, start playing with the saturation levels.
In the top one, I see the corner of a wall in the yellow area.
The bottom one looks like stairs in the yellow, and that they definitely used flash.
I looked at the site they came from, and saw a few more that had different things that looked like motion blur of a light. I wonder if these could be shot with ambient light, long shutter and then flashed?
There is a lot of cool stuff on that blog. Too bad I can't read it.
I had a light leak on a camera, and it was pretty regular, and never contained imagery.
The 1st one is 4s exposure with flash on and ISO 400. So ... I believe the ghost type lighting was from the long exposure and the subjects were lighted by the flash.
When using flash, you can set it to do a long exposure and flash on the rear curtain.
Meaning, the shutter will stay open for 4 seconds, and flash will fire right before the shutter closes. So the yellow color is caused by ambient light during the first 4 seconds.