One of the complaints about the Nexus 7 is the lack of storage and/or the lack of ability to expand that storage. At this stage the only option is to root your Nexus 7 and then use StickMount with an OTG Cable and USB Flash Drive.
Well, there is now an app in the market that does not require root to connect a USB Flash drive via USB OTG cable :Nexus Media Importer. You still require a USB OTG Cable which will cost you about $2 on eBay, you can then import and stream music, video and photos from a USB flash drive or SD card connected to your device running Android 3.2 and up.
The app costs $1.89 but the Developer has provided the app Nexus Photo Viewer for you to download free of charge to try out the implementation and make sure it works before you drop any money on it. I have rooted my Nexus 7, which unfortunately means I cannot test this app, however the comments look positive, so try out the free version and see how you go.
Update : The app was removed briefly, I emailed the Dev who got back to me and advised :
I was having issues keeping up with support and had to make a difficult decision about exFAT. After numerous requests, I put it back up (minus exFAT) and put people on notice that support could be slow.
Sorry for the inconvenience I caused everyone and thanks for your support.
So it’s back in the Play Store for download, go grab it, but be aware that it has no exFAT support, apart from that it’s good to go.