A new mode in Eye-Fi X2 cards let you rely images through a smartphone using a neat trick: I'm a long-time fan of the Eye-Fi digital camera cards that pack a CPU, a Wi-Fi radio, and now up to 8 GB of storage into an SD or SDHC form factor. The Eye-Fi line is regularly updated to add features like transfer of RAW images or video files, or endless storage, in which images already wirelessly transferred to another location can be deleted when storage is needed. (I haven't erased my Eye-Fi camera card since that feature came out. I simply don't need to know what's on the card any more.) Direct Mode is another in that array of improvements, and it requires a little explanation. Eye-Fi may be a bit breezy in describing the feature, which requires you to think a bit differently about how the card works. In regular operation, an Eye-Fi card looks to a camera precisely like any memory card.…