Oh hell yeah, that would totally work. I like the design of their website and iconography okay, but I think stuff like this could be the default. It's all logical, sensible, and distinct- very good job.
Why don't you stick with the shotwell original colors. RGB. The Back stays Blue, the front pic is green and the camera hue red, (but then again it might look like a record button than a camera) either way it would state still life. Always on. Always remembering. The thing is i like the format and structure of the icon but the icon could still stay intact with the original. Giving reference and honor. That's just me though. Love the work.
I think it would be clearer if the lens had some more detail. How about adding it an aperture? It's something very recognizable. [link] Also, the flower could use some more detail, I suppose you made it kind of fast there. Other than that, it's great!
You could add a bit of detail to the lens and, huh, think about what colours are still unused in your icons to give it a bit more of originality. I don't know if you get what I mean (i.e. Beatbox is orange, Yorba is yellow, Marlin is blue... maybe a bit of purple or brown for Shotwell?)
I love the whole orangy feel to it. Maybe don't do it, 'cuz that'll make this icon lose its colour identity. Change the colours to something else maybe, but avoid the primary ones. Every icon should be distinguishable with their colour aswell, instead of being a RGBY mashup everytime. For logos, such things dont matter 'cuz they aren't used as much as desktop icons.