IMGP1096 by silverfish51, on Flickr I'm not sure if it's the time of year or just me in general, but I'm finding it really hard of late to 'see' photographs within an environment.
Nobody else was taking this, so I'll have a bash. A vignette is, in it's simplest and most common form, a darkening at the edges of a shot. This can be caused by a lens, or can be added in post processing. It's generally undesirable to have a lens with heavy vignetting, as you'll get in on all your shots, whether you like it or not. It can often be a useful tool however to draw peoples focus into the centre of the shot. If you use Lightroom, the it's under the Effects tab as post crop Vignetting. I don't know how other programs deal with it. These are two pics with a fairly strong vignette. Wedding Toms by PGoodhead, on Flickr Nan by PGoodhead, on Flickr
Nice, there are loads of Red Kites around my parents' house, but I've never got a picture so close up
Some macro with a reverse-mounted kit lens @ f/8 Not quite as big as my last arachnid friend... (taken with 5D & Sigma 50mm) But lurvely big eyes (7D and reverse 18-55 @ 18mm)
I would have processed it much more carefully if it was paid work, but alas it's not. The second photo was taken at ISO 1600 and the exposure was bumped slightly in PP, so it's going to be grainy anyway.
Silhouette Blue Beauty by JazzXP, on Flickr I'm in two minds about the hair on her neck, whether it's a distraction, or if it balances the tattoo on her shoulder.