Hello,
to warn you right away: It’s not FLOSS. Buuuut you can use it in Linux and it’s just such a great Software to work on photographic projects. You can make sketches of Books or Websites or arrange your photoseries. It works like a desk where you can move images arround, resize Them,…
So it made thinks a lot easier for me and I thought it’s also nice for you.
pureref
UPDATE → There is also a FLOSS alternative. Check it out it has the same benefits for your photography workflow: https://beeref.org/
And here is a more detailed thread: Libre Arts - Introducing BeeRef
Wapitifass