The standard for inkjet resolution is 600×600 dpi (dots per inch), but you can find higher resolutions such as 1200×1200 dpi or 1440×1440 dpi or even 2880×1440 dpi, all of which are considered photographic quality. In general, you'll want to avoid lower resolutions. Don't insist on 1200 dpi unless you need high-quality photographic output. Keep in mind that many inkjets have different resolutions for color and monochrome.

Resolution isn't the only factor that determines the output quality of your photographic prints. You also need to know whether the printer offers resolution enhancement, and if it does, what kind. Edge enhancement typically varies the size or position of dots on edges of lines, text, and solid blocks. Because this feature smoothes edges, it can produce an apparent resolution nearly double the dpi rating. However, it won't improve continuous-tone images such as photos. For photos, you can get very different output quality at any given resolution, depending on how the printer creates shades of gray and shades of colors.