Glossaries can be very helpful tools, and whilst there are several glossaries around the Internet for various things, including photography (which often include stuff that are non-applicable), I thought hey - why not make one for specifically SL photography? Then I realised that making a complete glossary from start to finish is going to be rather a daunting task, and so I figured it might be worth having a go at making a forum thread about it where all the virtual shutterbugs are at and make it a team effort.
Simply add whichever words you think would fit into the subject, with a description of what it entails - or suggest changes to words already in the glossary (constructively and nicely, if possible). I'm going to throw a few in to get us started.
Aspect Ratio - the ratio of width to height, i.e. a 4:3 aspect ratio is 4 parts width to 3 parts height, whereas a 16:9 ratio is sixteen parts width to nine parts height (such as 2048 x 1536 and 1920 x 1080). Not to be confused with, but an important part of, resolution. The axes are X for width, and Y for height (unlike in-world building where, by default, X is from west to east, Y is from south to east, and Z is from down to up).
B&W - an abbreviation for 'black and white', images without colour (but generally with a wide grey tonal range).
Camera - the viewpoint of the user in Second Life; there is no virtual camera as in, the physical photography tool, but rather the position within the three-dimensional space from which the viewer renders the world.
Camera Roll - is a feature where the camera is rolled towards its sides, rotating in such a way that the horizon moves towards a diagonal angle, or even a vertical angle, or even an inverse angle (world goes upside down). The feature is only present in certain viewers, such as Black Dragon.
Candid - a first/real life term referring to a portrait of a person, taken without the subject posing for the camera, often achieved in street photography and event photography when the subject is unaware that their picture is being taken at that moment. I personally tend to use the term 'in AO-shot' as it's more descriptive, when referring to a picture taken of an avatar with their regular, moving animations running - but this is how I envision a virtual candid, or self-candid (rather than self-portrait).
Composition - refers to the arrangement and relation of everything in a picture, including elements within the frame, subject(s), props, backdrop, lighting, focus, contrast, bokeh, etc. There are countless rules of composition (rule of thirds, where limbs are cropped, harmony of angles, etc), but in the end a 'good' composition is a subjective matter.
Contrast - is the difference between shadows and lights (and colour) in an image. In a high contrast setting, you might have very dense shadows and very bright lights (short range and high falloff lights), whereas in a low contrast setting, the lighting may be flat and the colours more dull.
DoF/Depth of Field - is the relation of depth and focus in a picture, or 'how blurry do things far from the focal point get'. See blur.
Dutch Angle - is a term sprung from German Impressionism in early film history; unnatural angling made to cause an intentional, surreal visage meant to signal distress to the viewer. Employed artistically to this effect to this day in both photography and film (generally when a character on the screen suffers mental distress or fear, which isn't otherwise necessarily visible, frequently in unison with music or ambient noise to underscore the situation at hand). Also a slur for when people use camera roll to extreme effect.
Exposure - is the amount of light in your image. Whilst we generally don't have to worry about it (except if using the feature in Black Dragon), it is a common feature to be adjusted whilst editing (often in combination with contrast). Overexposure is when the exposure is so high that we suffer information loss in highlight areas (i.e. things that are fairly bright all go plain white and, thus, all henceforth have the same colour value).
FOV/Field of View - means how many degrees of vision (although generally counted in radians) that are projected to the viewer; see Zoom.
File Format - is how an image is saved. There are 3 formats available (in Firestorm, anyway) when saving your pictures with the snapshot tool; JPEG (Joint Photographic Experts Group), which is a compressed, lossy format (lighter file size, but at the cost of fidelity), BMP (Bitmap) is uncompressed and lossless (large or even enormous file size, with full fidelity), and PNG (Portable Network Graphics), which is compressed and lossless (file size may vary but are practically always smaller than BMP, whilst retaining full fidelity).
Side note: in most cases, you'll want to use PNG.
Fisheye Effect - is the optical distortion which causes warping towards the edges of an image. See Zoom and Warp.
Landscape - can either refer to a picture of a landscape, whether nature or architecture. It may contain people, but no one person is an overwhelming focus; the entire picture is supposed to be viewed as a complete entity.
It's also used as a term for a picture that is wider than it is tall (as opposed to a portrait image, where the opposite is true).
Monochrome - essentially a B&W image with a single colour tone (such as sepia).
Noise - is to photography what film grain is to, well, film. As noise is an effect of shutter speed (which, isn't really a thing in SL), it is usually added manually in editing. Whilst noise is largely considered a detriment of quality, it can be used for artistic effect.
Portrait - a picture wherein the focus (or 'subject') is of a person (avatar), or living being in general (the neighbour's dog, maybe?). Whilst artsy types may do tree-portraits, the term generally refers to an arranged image of a person (as opposed to a candid). Furthermore there are specific types of portraits, such as mug shots, passport photos, and post-mortem portraits.
Alternatively, a 'portrait picture' is an image wherein the aspect ratio is a larger Y axis than X axis, such as 3:4 as opposed to 4:3 (i.e. the picture is taller than it is wide).
Radian - denoted as rad(s) or simply r, is an SI unit for measuring angles. 2πr = 360°, or 1r = 57.296°. See Field of View and Zoom.
Raw - a picture that hasn't been edited or filtered ('photoshopped'). Though a rather vague term, since most viewers have various tools to adjust the specifics of how a picture is rendered, and have various in-viewer filters. Shooting raw is apparently brave, artistic, and virtuous, 'cause it's not like digital editing is the modern equivalent of much the same that was done to 'analogue photography' in darkrooms of the past or anything, and it's not like 'photoshopping' is, in any way, shape, or form, an artistic process in and of itself.
Resolution - is the size of an image in amount of pixels, usually counted in megapixels (1 MP = 1,000,000 pixels). Within SL, the resolution values must be divisible by 8 (8, 16, 32, 64, 128, 256, 512, 1024). An image that is 1024 x 1024 pixels is 1,048,576 - or roughly 1 MP. Outside of SL, you can use whichever aspect ratio you want, with whatever number of pixels you want; a 2:3 image with 500 x 750 pixels is 0.375 MP. The highest possible export setting in Firestorm is 6144 pixels on either axis, which means that the highest resolution possible would be 6144 x 6144 = 37,748,736 = 37,7 MP.
Not to be confused with file size, which is highly dependent on the image size and file compression method.
Higher resolution directly translates to higher detail, but also (practically) invariably higher file size (and thus, loading time) - also mind that native resolution and display resolution often means that a high resolution image must be compressed to be displayed on a monitor, which (also practically) invariably means loss of detail.
RGB - red, green, blue, is a format in which colours of any given pixel are described with a value of all three base colours combined, from 0-255 (for example, 255, 255, 0 = pure yellow, 0, 0, 0 = black and 255, 255, 255 = white).
Saturation - is the intensity of a colour. Within SL, saturation is simply a function of the Y axis of the colour picker, but the term is also relevant for describing colours in general.
Sepia - originally the name for an ink from the ink sacs of cuttlefish of the genus Sepia (I wonder where they got the name for the ink from!), the term these days describes the reddish-brown colour of said ink, and monochrome images of said tone.
Signature - is a mark, often towards a corner, often containing the name or brand logo of the photographer or their studio, added to a picture to ensure that viewers can (in theory) know who made the picture.
Tonal/Dynamic Range - describes the amount of different tones present in any given image/frame. A wide tonal range means that there are more shades, allowing a higher level of detail.
Vignette - is when the edges and, specifically, the corners of an image are darkened. Like film grain, this used to be an issue with equipment which has since become a frequently employed artistic feature.
Warp - or warping, is when things are distorted due to the field of view; lines that should be straight appear curved, as things are pressed in towards the centre of the lens. Generally considered very unflattering when it comes to portraits, and something best avoided unless employed as an artistic effect.
Watermark - is a method of protecting one's digital artwork to be unlawfully redistributed, by putting a faint pattern (often with the owner's name) across the image.
Zoom - is, essentially, the effect of the field of view. A higher zoom means a smaller field of view, which means that the objects within view appear closer (zoomed in), whereas a lower zoom means a larger field of view, which means that a larger area is compressed into the field of vision. In SL, zoom is expressed in radians (rads), with the default view of 1.042 rads (59.7022023 degrees) - having too high a field of view (low zoom) can cause the fish eye effect.
Anyway, I'm thinking that'll be a decent start - but feel free to toss in whatever words and terms you can come up with!