1. Dodge and Burn - The Dodge tool and the Burn tool lighten or darken areas of the image. These tools are based on a traditional darkroom technique for regulating exposure on specific areas of a print. Photographers hold back light to lighten an area on the print (dodging) or increase the exposure to darken areas on a print (burning). The more you paint over an area with the Dodge or Burn tool, the lighter or darker it becomes.
  2. Sponge - change saturation - either saturate (add color) or desaturate
  3. Blur, Sharpen, Smudge
  1. how to fix blemishes in photos
  2. Photo retouching
  3. filtering light issues
  4. Enhancing resolution
  5. Fixing bad photo quality

Pixel dimensions measure the total number of pixels along an image’s width and height. Resolution is the fineness of detail in a bitmap image and is measured in pixels per inch (ppi). The more pixels per inch, the greater the resolution. Generally, an image with a higher resolution produces a better printed image quality.