Photo Editing Glossary: 50 Terms Every Designer Should Know

Photo editing has its own vocabulary, and half of it gets thrown around without explanation. This glossary covers 50 terms you'll actually run into - as a designer, a marketer prepping images, or just someone trying to figure out why a photo looks blurry after resizing - each in one plain-language sentence.

File Formats

• JPEG (JPG) - a lossy compressed format best suited to photos; small file size, no transparency support.
• PNG - a lossless format that supports transparency, making it the default choice for logos, graphics, and cutouts.
• WebP - a modern format with both lossy and lossless modes that produces smaller files than JPEG or PNG at equivalent quality.
• HEIC - Apple's default photo format on iPhone, roughly half the file size of an equivalent-quality JPEG.
• GIF - a format limited to 256 colors that supports simple frame-based animation.
• BMP - an uncompressed raster format; large file sizes with no compression benefit.
• TIFF - a lossless format common in scanning, printing, and archival workflows.
• SVG - a vector format defined by math rather than pixels, so it scales to any size with zero quality loss.
• RAW - unprocessed sensor data straight from a camera, before it's been converted to a standard image format.
• AVIF - a newer, highly efficient format based on the AV1 video codec, often smaller than WebP at the same quality.

See Image File Formats Explained for a full breakdown of when to use each one, or jump straight to Convert Images to switch between them.

Color & Tone

• RGB - the additive color model (red, green, blue) that screens use to display color.
• CMYK - the subtractive color model (cyan, magenta, yellow, black) used for professional printing.
• Hex code - a 6-character code (like #FF5733) representing a single RGB color, used constantly in web design.
• Saturation - how intense or "pure" a color appears; low saturation looks washed out, high saturation looks vivid.
• Contrast - the difference between the darkest and lightest tones in an image.
• Hue - the base color itself (red, blue, green) independent of how light, dark, or saturated it is.
• White balance - the correction that removes an unwanted color cast (too orange, too blue) caused by lighting conditions.
• Color grading - a deliberate, stylistic adjustment of color and tone across an image, beyond basic correction.
• Histogram - a graph showing how many pixels fall at each brightness level, from pure shadow to pure highlight.
• Color space - the defined range of colors a device or format can represent, such as sRGB (web) or Adobe RGB (print).

Resolution & Sizing

• Resolution - an image's total pixel dimensions, expressed as width x height (e.g. 1920x1080).
• DPI - dots per inch; a measure of print density that determines how sharp an image looks on paper.
• PPI - pixels per inch; the screen equivalent of DPI, describing display density.
• Aspect ratio - the proportional relationship between an image's width and height (e.g. 16:9, 1:1).
• Upscaling - enlarging an image beyond its native resolution by estimating new pixel values, since no new detail actually exists to recover.
• Downsampling - reducing an image's pixel dimensions, which is generally lossless in the sense that detail is only removed, never fabricated.
• Interpolation - the method used to calculate new pixel values whenever an image is resized up or down.
• Bit depth - the number of bits used to represent color per pixel; higher bit depth means smoother gradients and more distinct colors.
• Native resolution - an image's original, unaltered pixel dimensions before any resizing.
• Print size - the physical output size of an image, calculated from its resolution divided by the chosen DPI.

Need to actually resize something? Resize Images handles exact pixel dimensions and common presets in the browser.

Transparency & Layers

• Alpha channel - an extra image channel that stores transparency information alongside color; it's what makes a PNG background see-through.
• Clipping path - a defined outline used to isolate part of an image, hiding everything outside it - the traditional, manual way to cut out a subject.
• Masking - hiding part of an image non-destructively, without permanently deleting any pixels.
• Layers - stacked, independently editable elements that combine to form a final composite image.
• Opacity - how transparent or solid a layer or element appears, from fully invisible to fully opaque.

Modern background removal tools produce a clean alpha channel automatically - no manual clipping path required.

Compression & File Size

• Lossy compression - compression that discards some image data to shrink file size, trading a bit of quality for a much smaller file (JPEG, lossy WebP).
• Lossless compression - compression that shrinks file size without discarding any image data at all (PNG, lossless WebP).
• Metadata / EXIF - embedded information about an image, like camera settings, capture date, and sometimes GPS location.
• Dithering - a technique that uses patterns of pixels to simulate colors or gradients a format can't represent directly, common in GIFs with limited palettes.
• Artifact - a visible flaw, like blockiness or color banding, introduced by aggressive lossy compression.

Compress Images handles the lossy/lossless trade-off for you with a quality slider, rather than requiring you to guess the right settings.

Editing Effects

• Vignette - darkened or faded edges around an image that draw the eye toward the center.
• Bokeh - the soft, pleasant blur of out-of-focus areas in a photo, especially background lights.
• Sharpening - a filter that increases edge contrast so an image appears more detailed and crisp.
• Noise reduction - smoothing out grain or speckling, usually from photos taken in low light.
• Feathering - softening the edge of a selection or cutout so it blends into its new background instead of looking pasted on.
• Pixelation - deliberately blocking out detail (often to redact a face or sensitive information) or the degraded look that results from stretching a small image too far.
• Watermark - a text or logo overlay used to mark ownership or discourage unauthorized reuse of an image.
• Anti-aliasing - smoothing the jagged, stair-step look of curves and diagonal lines at the pixel level.
• Moiré - an unwanted wavy pattern that appears when two fine repeating details overlap, like photographing a striped shirt or a screen.
• Batch processing - applying the same edit - resize, format conversion, watermark, or otherwise - to many images at once instead of one at a time.

Most of these effects map directly to a Snipinsta tool: Add Watermark for the last one, Photo Filters for vignette and tone effects, and Detect Faces for automatic pixelation/blur.

Frequently Asked Questions

Recap: bookmark this page for quick reference, and put the terms to work with Convert Images, Resize Images, or Compress Images - all free, all in the browser.