Filemaker has made it pretty clear that native droid support is not anything they're interested in for the near future.
That being said, if inserting a picture into a container through IWP isn't natively supported (IE, choosing a file itself from the phone) there are some options.
Check out FMDroid (an XML/WPE client for droid)
Also check out 24U's IWP picture upload utility:
It might take a combination of things (Including some CWP in place of IWP), but in the end you should be able to make something that works for you.