Toshiba's FlashAir II offers a handy solution, embedding a miniature Wi-Fi access point into a standard SD card. Just like that, you can access photos on the card from up to seven other devices, connecting directly via Wi-Fi to the card's access point.
If this sounds familiar, you're probably thinking of the venerable Eye-Fi line of products, which combine an SD card and a wireless radio, giving your camera instant wireless capabilities. But Eye-Fi and FlashAir work quite differently. With Eye-Fi, your camera connects to an existing wireless network, which it uses to upload photos to the cloud or another PC on the LAN. FlashAir doesn't require an existing network—in fact, it can't connect to an existing network. Rather, FlashAir is its own wireless LAN, and you configure your other devices to connect to it.