thumbimage

Generates and displays a thumbnail image of the size specified by the URL parameter.
The Origin header is checked in the program. This prevents the image generation process from running if the URL is entered directly or embedded from another site without permission.
If a thumbnail image has already been generated (in the case of the second or later requests), the generated image will be displayed instead of processing the generation.
If the original image has been updated (the file's modified date is newer than the thumbnail image), the generation process will be repeated.

URL Parameters

e.g. /thumbimage/path/to/sample.jpg?type=webp;w=360;h=240;quality=30

The type, width, height, and quality can be specified in the URL parameters.

Image Type	URL parameters
Image Type	`type` (Required)	`w`	`h`	`quality`
AVIF	`avif`	`1`-`9999`	`1`-`9999`	`1`-`100` (default: 80)
WebP	`webp`
JPEG	`jpeg`
PNG	`png`			✘ (ignore)

The type parameter can be singular or multiple. If multiple values are specified, the image will be displayed based on the Accept request header.

`Accept` request header	`type` parameters	Response image type
image/webp,/	`type=avif`	AVIF (Cannot be displayed)
	`type[]=avif;type[]=webp;type[]=jpeg`	WebP
	`type[]=jpeg;type[]=webp;type[]=avif`	WebP
image/avif,image/webp,/	`type=avif`	AVIF
	`type[]=avif;type[]=webp;type[]=jpeg`	AVIF
	`type[]=jpeg;type[]=webp;type[]=avif`	AVIF

If the parameter w or h is larger than the size of the original image, thumbnails will be generated at the size of the original image.

Original image size	URL parameters	Generated image size
1920×1280	`w=9999;h=9999`	1920×1280
	`w=9999;h=640`	960×640
	`w=360;h=640`	360×240
	`w=9999`	1920×1280
	`h=640`	960×640
	(not specified)	1920×1280

If the value of the parameter is invalid, return 403 Forbidden. (e.g. ?type=xxx;w=10000;h=10000;quality=0)

Sample

Original file

Image file

Path: /image/sample.jpg
Type: JPEG
Width: 1920px
Height: 1280px
Quality: 80

Generated thumbnail image

Optimal image type selection by using the `picture` element

<picture>
	<source type="image/avif" srcset="/thumbimage/sample.jpg?type=avif;w=360;quality=30" />
	<source type="image/webp" srcset="/thumbimage/sample.jpg?type=webp;w=360;quality=30" />
	<img src="/thumbimage/sample.jpg?type=jpeg;w=360;quality=30" alt="Sample Image" crossorigin="" />
</picture>

Sample Image

Optimal image type selection by using the `accept` request header

<img src="/thumbimage/sample.jpg?type[]=avif;type[]=webp;type[]=jpeg;w=360;quality=30" alt="Sample Image" crossorigin="" />