Background: The digital image has become an important tool in dermatology because of the rapid development of computer hardware, networks, and the World Wide Web. Objective: Our purpose was to examine the resolution requirements for digital images. Methods: Slides of eight selected images showing characteristic lesions were produced in five different resolutions each, ranging from 192 × 128 × 24 (192 pixels x, 128 pixels y, and 24-bit color depth) up to 3072 × 2048 × 24. They were compared side by side by a group of six experienced dermatologists using a standardized questionnaire. Results: Images at the resolution of 768 × 512 × 24 were perceived as equivalent to higher resolutions, whereas a clear difference was visible between 768 × 512 × 24 and 384 × 256 × 24. The slide projector had a significant influence on the rating of the images. Conclusion: For digital images in dermatology a resolution of 768 × 512 × 24 is suitable to recognize the relevant details of the source image. (J Am Acad Dermatol 1997;37:195-8.)