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Format

Controls the output properties of the image.

Adaptive filter &af

Use adaptive row filtering for reducing the PNG file size. This only works when the output image is png.

Base64 (data URL) &encoding=base64

Encodes the image to be used directly in the src= of the <img>-tag. Use this link to see the output result.

More info: Issue #59 - Return image base64 encoded.

//wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&crop=100,100,720,530&encoding=base64

Cache-Control &maxage=

Defines for how long an image should be cached by the browser. This will change the max-age of the Cache-Control HTTP-header.

We define a "far-future expiration" of 1 year by default. The duration can be specified in days, weeks, months, and years using the following suffixes:

  • d: days
  • w: weeks, 7 days
  • M: months, 30 days
  • y: years, 365 days

A duration must be in the range of 1d (1 day) to 1y (1 year), inclusive. Any other value will be ignored and fallback to the default value of 1 year.

More info: Issue #186 - Increase Cache-Control: max-age= to 1 year instead of 1 month.

//wsrv.nl?url=wsrv.nl/lichtenstein.jpg&w=100&maxage=31d

Compression level &l=

The zlib compression level. Use a value between 0 (no Deflate) and 9 (maximum Deflate). The default value is 6. This only works when the output image is png.

Lossless compression &ll

Whether the resulting image should be lossless compressed. This only works when the output image is webp.

More info: Issue #386 - webP output is always lossy and cannot be requested as lossless.

Default image &default=

If there is a problem loading an image, then an error is shown. However, there might be a need where instead of giving a broken image to the user, you want a default image to be delivered.

More info: Issue #37 - Return default image if the image's URL not found.

The URL must not include a default querystring (if it does, it will be ignored).

Use &default=1 to redirect to the original URL specified in ?url=.

html
<img src="//wsrv.nl/?url=example.org/noimage.jpg&default=wsrv.nl/placeholder.svg">
md
![Default image](https://wsrv.nl/?url=example.org/noimage.jpg&default=wsrv.nl/placeholder.svg)

Default image

Filename &filename=

To specify the filename returned in the Content-Disposition header. The filename must only contain alphanumeric characters.

More info: Issue #122 - Specify filename.

Interlace / progressive &il

Adds interlacing to GIF and PNG. JPEGs become progressive.

More info: Issue #50 - Add parameter to use progressive JPEGs.

html
<img src="//wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&il">
md
![Interlace / progressive](https://wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&il)

Interlace / progressive

Number of pages &n=

To select the number of pages to render. The default value is 1. Set to -1 to mean "until the end of the document".

TIP

-1 will be useful if you need to resize an animated WebP or GIF image.

html
<img src="//wsrv.nl/?url=wsrv.nl/banana.webp&h=300&output=gif&n=-1">
md
![Number of pages](https://wsrv.nl/?url=wsrv.nl/banana.webp&h=300&output=gif&n=-1)

Number of pages

Output &output=

Encodes the image to a specific format. Accepts jpg, png, gif, tiff, webp or json. If none is given, it will honor the origin image format.

More info: Issue #62 - Format conversion.

html
<img src="//wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&output=webp">
md
![Output](https://wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&output=webp)

Output

Page &page=

To load a given page (for an PDF, TIFF and multi-size ICO file). The value is numbered from zero. For a multi-resolution image, you can use -1 to get the largest page and -2 to get the smallest page.

Quality &q=

Defines the quality of the image. Use values between 1 and 100. Defaults to 80. This only works when the output image is jpg, tiff or webp.

html
<img src="//wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&q=20">
md
![Quality](https://wsrv.nl/?url=wsrv.nl/lichtenstein.jpg&w=300&q=20)

Quality