@Nari they're supposed to show that the previous few panels were a flash back. They made more sense in the Japanese site's manga reader that had panel transition effects instead of just still images.
@Nari you weren't the only person to say that. I deleted the duplicate panel because it's purpose wasn't obvious to everyone and I added a black background to show it is a flashback. Parts at the beginning of the chapter were also flashbacks (her trying to rescue the cat in the tree) but it was obvious that was a flashback so I didn't add a black background to that.