A user named "I Pwnd U" found a glitch similar to the Kid Icarus: Uprising glitch, and has started posting pictures from other software in the Mario & Luigi: Dream Team Community. Thanks to this, users have been posting things such as SSB4 content, cartoons, art, real-life selfies, and memes. 
How the glitch can be performed
"This only works without the update for the game. You open another game or application that can be suspended, then you launch Dream Team. Rapidly press the HOME button repeatedly so that you will return to the HOME Menu the second that the 3DS logo is gone."
"Then rapidly press the HOME button repeatedly again to go back to the game for a second and return to the HOME Menu. This will cause the game to display an image from your previous software (in this case the camera app), or just random colors. This is most likely due to some data from the previous software remaining in the RAM."