byjp.me
A tool for archiving & converting scans of postcards, and information about them.
1# Web postcard format
2
3The most versatile of the formats, the Web format holds both sides of the postcard within one image (the front above the back). The image contains [XMP](xmp.md) metadata that fully describes the postcard, so this format is also suitable for archive purposes.
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5If the postcard is 'heteroriented' (the back and front have different orientations) then the lower half will be rotated 90º clockwise (for left-hand flip postcards), or 90º anti-clockwise (for right-hand flip postcards), so that a Web format postcard is always the same width as the front of the postcard, and twice the height of the front.
6
7> [!TIP]
8> By default this format uses lossy JPEGli compression and resizing to make a small but high quality image. If your input images use transparency, or if you request an 'archival' quality postcard, then it will produce a WebP format image that can support what you've requested.
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10## Example
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12The following three output formats will create a Web format postcard that makes use of the HTML & CSS files to show the postcard in a visually appealing way.
13
14```sh
15$ postcards -f web,css,html pyramids-front.jpg
16⚙︎ Converting 1 postcard into 3 different formats…
17pyramids-front.jpg (Component files) → (Web) pyramids.postcard.jpg
18pyramids-front.jpg (Component files) → (CSS) postcards.css
19pyramids-front.jpg (Component files) → (HTML) pyramids.html
20```