How do I post a 3DS screenshot? Update your 3DS to the latest firmware, allowing registration of (or linking to) an NNID and access to Miiverse. During play press the Home button to pause the game. Access Miiverse, and post your image on the service. Using your PC, access Miiverse to find your post. Save your image, and upload it to abload, imgur, or whatever. Post here.
Finding your image URL on Miiverse can be tricky. Here's some instructions:
You can also right click on the image, select "Inspect Element", then hit the drop down arrow to the right of the automatically highlighted <div class="screenshot-container">. This will show you an <img scr=URL that you can click on to directly access the image, save it, and upload to an image sharing service.
Man, those 3DS pictures are smallish but perfectly sized for the resolution of the screen. On the other hand, the massively sized Vita captures aren't doing the material any favours at all as compared to how it actually looks like on the screen. Especially if the game was subnative to begin with. You can really see which games are rendering at native from the posted ones.
EDIT:- Oh wait, those are direct screencaps aren't they? Just noticed the picture info from the posted screenshots. 400x240 is really that much smaller than 960x544.