Normally a thumbnail has a width of 220 pixels (px). This width is used by typical readers, who have not logged in or who have not changed their preferences. The "upright" option normally creates an image that is about 75% of the width of the default. The exact width is computed by starting with the default thumbnail width, multiplying it by 0.75, and rounding to the nearest multiple of 10.
Standard behaviour (upright not specified)
The standard behaviour can make a tall, thin picture come out too large. For example:
[[File:Amun.svg|thumb|alt=Full-length profile of man in ancient Egyptian clothing. He has red-brown skin and wears a helmet with tall yellow plumes.|The Egyptian god Amun, portrayed before the Amarna period]]
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Upright images
The "upright" option can help fix this by informing the Wikipedia layout system that the image should have a narrower width than usual:
[[File:Amun.svg|thumb|"Upright"|alt=Full-length profile of man in ancient Egyptian clothing. He has red-brown skin and wears a helmet with tall yellow plumes.|The Egyptian god Amun, portrayed before the Amarna period]]
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
- Shrinking upright images further
If the upright factor 0.75 is too large or too small, it can be specified explicitly. A factor of 1.0 uses the default thumbnail width, which is the same as not specifying "upright" at all; a factor less than or greater than 1.0 creates an image smaller or larger than the default. For example:
[[File:Amun.svg|thumb|upright 0.75|alt=Full-length profile of man in ancient Egyptian clothing. He has red-brown skin and wears a helmet with tall yellow plumes.|The Egyptian god Amun, portrayed before the Amarna period]]
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Short, wide images
Short, wide images sometimes benefit from "upright" factors greater than 1.0. Factors greater than about 2.5 can generate large images that cause problems with some browsers; for one way to handle wider images, see panoramas. Although many image types, such as JPEG and PNG, do not handle enlargement well, SVG images have no problem with it. For example:
[[File:Köppen-vereinfacht.svg|thumb|center|upright=2.0|alt=Map of the world. A tan band stretches from northern Africa through central China; most of Australia and parts of southern Africa and the western Americas are also tan. Dark greens dominte the northern hemisphere. Lighter greens cover much land near the equator. Polar areas are white, the north fringed with light blue.|Macroclimates of the earth. Tans represent desert, dark greens humid continental, and light green tropical rainforest. Light blue and white represent tundra and ice cap.]]