Dodging
Dodging is making a section of a photo lighter. When this is done in the darkroom, it's usually by blocking some of the light from reaching that part of the picture. In a photo editing program, it's a paintbrush like tool that lightens instead of painting.
Download
Downloading is the opposite of uploading. Downloading means to pull data from another location. Normally it means to get data from the Internet, but in digital photography, it also means to get the pictures from the camera. Sometimes used interchangeably with Importing.
DPI
Most photo printers and monitors measure their resolution in Dots Per Inch, or DPI. The higher the number, the higher the resolution.
EXIF
EXIF stands for Exchangeable Image Format. Most digital images have two parts. The first is the image itself, which is usually stored as a JPG image. The second is the EXIF data. EXIF data most often includes all of the photographer's information, like the date and time the picture was taken and the shutter speed and aperture set at the time.
Flip
Flipping an image is the same as reflecting it in a mirror. Flipping is one of the basic image editing tools.
Grayscale
Technically speaking, a spectrum of gray shades from black to white. A grayscale picture is the digital equivalent of a black and white photo.
Highlights
The Highlights are the whitest part of a picture. Normally, they are a very small percentage of the picture, because it's very easy to lose details in highlights.
Histogram
A Histogram is a chart that graphs all of the tones in a photo. Most programs will generate histograms, and most digital cameras can create them also.
Image File Format
The format of an image file determines the size of the file, the overall image quality, and several other things. Common image file formats are JPG, GIF, TIFF, and PNG.