UniWiki:Manual of Style/Images: Difference between revisions

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===Consideration of image download size===

Images can greatly increase the [[bandwidth (computing)|bandwidth]] cost of viewing an article{{snd}}a consideration for readers on slow or expensive connections. Articles carry reduced-size [[~~thumbnail~~]]s instead of full images (which the user can view by "clicking through" the thumbnail) but in some file types a thumbnail's reduced dimensions doesn't translate into a concomitant reduction in file size. (In most browsers you can see a thumbnail's size by right-clicking for its "Properties".)

Images can greatly increase the [[Wikipedia:bandwidth (computing)|bandwidth]] cost of viewing an article{{snd}}a consideration for readers on slow or expensive connections. Articles carry reduced-size [[Wikipedia:Thumbnail|thumbnails]] instead of full images (which the user can view by "clicking through" the thumbnail) but in some file types a thumbnail's reduced dimensions doesn't translate into a concomitant reduction in file size. (In most browsers you can see a thumbnail's size by right-clicking for its "Properties".)

If one image's file size is disproportionate to those of others in the same article, you may want to reduce it by selecting a different file format:

* [[GIF]] images with a frame size larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) cannot currently be displayed in thumbnail form in Wikipedia articles. A thumbnail of a GIF image can be considerably larger in kilobytes than the original image file.

* [[Wikipedia:GIF|GIF]] images with a frame size larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) cannot currently be displayed in thumbnail form in Wikipedia articles. A thumbnail of a GIF image can be considerably larger in kilobytes than the original image file.

* Animated [[GIF]] images have a few additional restrictions. Images larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) currently will only show the first frame of the animation in a thumbnail. When not using a GIF animation at its original frame size, consider creating an Ogg [[Theora]] movie of the animation.

* Animated [[Wikipedia:GIF|GIF]] images have a few additional restrictions. Images larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) currently will only show the first frame of the animation in a thumbnail. When not using a GIF animation at its original frame size, consider creating an Ogg [[Wikipedia:Theora|Theora]] movie of the animation.

* The [[Portable Network Graphics|PNG]] format is useful for storing graphics that contain text, line art, or other images with sharp transitions. It can achieve the same graphical results as a GIF file, and in many cases do so with a higher rate of [[file compression]]. For this reason, PNG format files are usually preferred to the GIF format. (However, for certain types of images, PNG thumbnailing is not as efficient as GIF thumbnailing, when Wikimedia GIF thumbnailing is enabled.) For images with substantial editing, or for which further editing may be warranted, uploading a PNG as well as a JPEG is common (PNG is lossless compression, so repeatedly saving edits on a PNG will not result in loss of quality.)

* The [[Wikipedia:Portable Network Graphics|PNG]] format is useful for storing graphics that contain text, line art, or other images with sharp transitions. It can achieve the same graphical results as a GIF file, and in many cases do so with a higher rate of [[Wikipedia:File compression|file compression]]. For this reason, PNG format files are usually preferred to the GIF format. (However, for certain types of images, PNG thumbnailing is not as efficient as GIF thumbnailing, when Wikimedia GIF thumbnailing is enabled.) For images with substantial editing, or for which further editing may be warranted, uploading a PNG as well as a JPEG is common (PNG is lossless compression, so repeatedly saving edits on a PNG will not result in loss of quality.)

* A [[JPEG]] or other compressed image format can be much smaller than a comparable GIF or PNG format file. When there is no apparent difference in quality, such as with a photograph that has no sharp graphical transitions, a compressed image format such as JPEG may be preferable for reasons of download performance. Wikipedia is often able to achieve much better compression of JPEG photograph thumbnails than comparable PNG images, and with little perceptible loss of quality. Repeatedly loading and resaving an image as JPEG will result in loss of quality, however, as will using low settings for the JPEG; as such, if you've made edits, it can be helpful to save a PNG or TIFF copy before closing the image editor and upload that as well; this copy can then be used to generate a new JPEG after further editing.

* A [[Wikipedia:JPEG|JPEG]] or other compressed image format can be much smaller than a comparable GIF or PNG format file. When there is no apparent difference in quality, such as with a photograph that has no sharp graphical transitions, a compressed image format such as JPEG may be preferable for reasons of download performance. Wikipedia is often able to achieve much better compression of JPEG photograph thumbnails than comparable PNG images, and with little perceptible loss of quality. Repeatedly loading and resaving an image as JPEG will result in loss of quality, however, as will using low settings for the JPEG; as such, if you've made edits, it can be helpful to save a PNG or TIFF copy before closing the image editor and upload that as well; this copy can then be used to generate a new JPEG after further editing.

* Where an image consists solely of line art, charts text and simple graphics, an [[Scalable Vector Graphics|SVG]] file can be significantly smaller than other graphics formats. This is because the data is encoded as a series of drawing commands, rather than as [[raster graphics]]. There are [[open source]] applications available for rendering graphics in SVG format. However, SVG thumbnails are rendered as PNGs.

* Where an image consists solely of line art, charts text and simple graphics, an [[Wikipedia:Scalable Vector Graphics|SVG]] file can be significantly smaller than other graphics formats. This is because the data is encoded as a series of drawing commands, rather than as [[Wikipedia:Raster graphics|raster graphics]]. There are [[Wikipedia:Open source|open source]] applications available for rendering graphics in SVG format. However, SVG thumbnails are rendered as PNGs.

* Rather than including an image gallery on an article, which could add significantly to the download size, consider creating a gallery/category on the Wikimedia Commons instead.

@@ Line 174: / Line 174: @@
 ===Consideration of image download size===
-Images can greatly increase the [[bandwidth (computing)|bandwidth]] cost of viewing an article{{snd}}a consideration for readers on slow or expensive connections. Articles carry reduced-size [[thumbnail]]s instead of full images (which the user can view by "clicking through" the thumbnail) but in some file types a thumbnail's reduced dimensions doesn't translate into a concomitant reduction in file size. (In most browsers you can see a thumbnail's size by right-clicking for its "Properties".)
+Images can greatly increase the [[Wikipedia:bandwidth (computing)|bandwidth]] cost of viewing an article{{snd}}a consideration for readers on slow or expensive connections. Articles carry reduced-size [[Wikipedia:Thumbnail|thumbnails]] instead of full images (which the user can view by "clicking through" the thumbnail) but in some file types a thumbnail's reduced dimensions doesn't translate into a concomitant reduction in file size. (In most browsers you can see a thumbnail's size by right-clicking for its "Properties".)
 If one image's file size is disproportionate to those of others in the same article, you may want to reduce it by selecting a different file format:
-* [[GIF]] images with a frame size larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) cannot currently be displayed in thumbnail form in Wikipedia articles. A thumbnail of a GIF image can be considerably larger in kilobytes than the original image file.
+* [[Wikipedia:GIF|GIF]] images with a frame size larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) cannot currently be displayed in thumbnail form in Wikipedia articles. A thumbnail of a GIF image can be considerably larger in kilobytes than the original image file.
-* Animated [[GIF]] images have a few additional restrictions. Images larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) currently will only show the first frame of the animation in a thumbnail. When not using a GIF animation at its original frame size, consider creating an Ogg [[Theora]] movie of the animation.
+* Animated [[Wikipedia:GIF|GIF]] images have a few additional restrictions. Images larger than 12.5 million pixels (measured as pixel height × pixel width × number of frames in the animation) currently will only show the first frame of the animation in a thumbnail. When not using a GIF animation at its original frame size, consider creating an Ogg [[Wikipedia:Theora|Theora]] movie of the animation.
-* The [[Portable Network Graphics|PNG]] format is useful for storing graphics that contain text, line art, or other images with sharp transitions. It can achieve the same graphical results as a GIF file, and in many cases do so with a higher rate of [[file compression]]. For this reason, PNG format files are usually preferred to the GIF format.  (However, for certain types of images, PNG thumbnailing is not as efficient as GIF thumbnailing, when Wikimedia GIF thumbnailing is enabled.) For images with substantial editing, or for which further editing may be warranted, uploading a PNG as well as a JPEG is common (PNG is lossless compression, so repeatedly saving edits on a PNG will not result in loss of quality.)
+* The [[Wikipedia:Portable Network Graphics|PNG]] format is useful for storing graphics that contain text, line art, or other images with sharp transitions. It can achieve the same graphical results as a GIF file, and in many cases do so with a higher rate of [[Wikipedia:File compression|file compression]]. For this reason, PNG format files are usually preferred to the GIF format.  (However, for certain types of images, PNG thumbnailing is not as efficient as GIF thumbnailing, when Wikimedia GIF thumbnailing is enabled.) For images with substantial editing, or for which further editing may be warranted, uploading a PNG as well as a JPEG is common (PNG is lossless compression, so repeatedly saving edits on a PNG will not result in loss of quality.)
-* A [[JPEG]] or other compressed image format can be much smaller than a comparable GIF or PNG format file. When there is no apparent difference in quality, such as with a photograph that has no sharp graphical transitions, a compressed image format such as JPEG may be preferable for reasons of download performance. Wikipedia is often able to achieve much better compression of JPEG photograph thumbnails than comparable PNG images, and with little perceptible loss of quality. Repeatedly loading and resaving an image as JPEG will result in loss of quality, however, as will using low settings for the JPEG; as such, if you've made edits, it can be helpful to save a PNG or TIFF copy before closing the image editor and upload that as well; this copy can then be used to generate a new JPEG after further editing.
+* A [[Wikipedia:JPEG|JPEG]] or other compressed image format can be much smaller than a comparable GIF or PNG format file. When there is no apparent difference in quality, such as with a photograph that has no sharp graphical transitions, a compressed image format such as JPEG may be preferable for reasons of download performance. Wikipedia is often able to achieve much better compression of JPEG photograph thumbnails than comparable PNG images, and with little perceptible loss of quality. Repeatedly loading and resaving an image as JPEG will result in loss of quality, however, as will using low settings for the JPEG; as such, if you've made edits, it can be helpful to save a PNG or TIFF copy before closing the image editor and upload that as well; this copy can then be used to generate a new JPEG after further editing.
-* Where an image consists solely of line art, charts text and simple graphics, an [[Scalable Vector Graphics|SVG]] file can be significantly smaller than other graphics formats. This is because the data is encoded as a series of drawing commands, rather than as [[raster graphics]]. There are [[open source]] applications available for rendering graphics in SVG format. However, SVG thumbnails are rendered as PNGs.
+* Where an image consists solely of line art, charts text and simple graphics, an [[Wikipedia:Scalable Vector Graphics|SVG]] file can be significantly smaller than other graphics formats. This is because the data is encoded as a series of drawing commands, rather than as [[Wikipedia:Raster graphics|raster graphics]]. There are [[Wikipedia:Open source|open source]] applications available for rendering graphics in SVG format. However, SVG thumbnails are rendered as PNGs.
 * Rather than including an image gallery on an article, which could add significantly to the download size, consider creating a gallery/category on the Wikimedia Commons instead.