Adapting Published Projects

I've written a number of short stories that have been published mostly in small online publications. But for the purposes of this question I'm not sure that matters.

I mostly write flash fiction and short stories. My question is say I write a flash fiction piece called Chicken Nuggets and it gets published, but I retain the rights. Then, a few months later, I turn the flash fiction piece called Chicken Nuggets into a much, much, much longer short story, or maybe a short film, or maybe a screenplay, or maybe a novel... point is I'd be taking one story I wrote and got published and turning into a new project of sorts, but still using the original within the new project.

Assuming the above makes sense, what of it? No big deal? Big no no?

Say I publish a flash fiction story, something like 400-600 words...

Then, a few months later, I expand it into like, 2000-5000 words...

Assuming the original flash fiction piece is within the new piece, can I still sell the first publication rights for the new short story that happens to hold the old flash fiction piece within it's body?

The reason I ask is because I wonder what would happen if the editor did a google search and happened to find the original flash fiction piece, if they would look down on that or not.

Would I need to clarify in submissions that the new story is "based on so and so, a flash fiction piece published in so and so?" Or is that not neccsary?

BenPanced said:

Instead of going from flash to short to novella to novel, why not just jump directly to the novel?

Click to expand...

I'm working on several screenplays and novels, but I also like to sit down and write some flash and shorts on occasion... it's easier to do and it's easier to publish. Faster, anyway.

When I write a flash fiction piece, I usually don't have a full length story in mind. However, sometimes after writing it, after it gets published, I suddenly think of a longer more awesome version...