Resizr

Resizr is a lightweight image resizer / thumb generator for PHP. Unlike other "mainstream" thumb generators, Resizr keeps the correct aspect ratio of the images, while keeping the maximum sizes below the ones you've set. It also compresses your images to speed up page loading times.

Supported image extensions

Currently, Resizr supports the conversion of JPEG, PNG, BMP and WEBP images.

How to use

Place resizr.php in a public accessible folder inside your web server. You will also need to create a cache folder in the same directory (or somewhere else, you can change this folder location in the user settings - see below). This folder must have writing permissions.

Now, in your HTML code refer your image URLs to the location of resizr.php file, along with one or more valid parameters appended to the URL query string.

Example

<img src="resizr.php?src=images/myImage.png&w=500&h=500">

URL parameters

Parameter	Type	Required	Default	Details
`src`	string	yes	-	Must be a relative or absolute URL for a supported image file.
`w`	int	no	200	Max desired width for the resized image.
`h`	int	no	200	Max desired height for the resized image.

Cache and performance

When calling Resizr, the script will check if the image you are loading was already generated in the desired sizes. If so, Resizr will load the cached image, otherwise it will generate the new image and store it in the cache folder for future calls. This optimizes the script performance and reduces server load.

User settings

In resizr.php file, between the lines 14-36 you can find Resizr user settings. You are free to edit this settings to fill your needs.

Setting	Type	Default	Details
`cache_folder`	string	cache	Cache storage folder location. This folder is relative to the script file path. It must have writing permissions!
`allow_external`	bool	false	Allow Resizr to load images outside the script server. Leaving this setting on is not recommended, as it may have security impacts. Use with caution.
`default_width`	int	200	Default max width to use when the `w` URL parameter is not specified.
`default_height`	int	200	Default max height to use when the `h` URL parameter is not specified.
`jpeg_quality`	int	70	JPEG quality level to use while compressing images. Goes from 0 (worst quality) to 100 (best quality).
`png_compression`	int	3	PNG compression level to use while compressing transparent images. Goes from 0 (no compression - best quality) to 9 (heavy compression - worst quality).
`keep_transparency`	bool	true	Keep transparency in PNG and WEBP images (if false, all images will be converted to JPEG).
`fill_color`	array	[255, 255, 255]	If `keep_transparency` is disabled, the color to fill the alpha channel (array with R, G and B color values).

eugabrielsilva / resizr