About you memory:
Inactive means that this memory was recently used but is not cleared.
It is left inside your memory incase you reopen the application again.
See it as some kind of cache.
You can force a clean up with Terminal > 'purge' command.
So everything is ok with that... In general, this is a reason why your mac is so fast

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About the additional task: iPhoto seems to make some conversion.
You can klick on the process and see for further information.