thumbc.php

<?php
/*
Put this file in Kirby plugins/thumbc/thumbc.php
Find cacert.pem on the web and put it in the same folder
Add c::set('tinypngKey', 'your_API_key'); to your config with your TinyPNG API key
Add echo nail( $page->image( 'screenshot-1.png' ), array( 'width' => 300 ) ); to your header.php to see if it works
*/

function nail( $image, $args ) {
	$class = new Foo( $image, $args );
	return $class;
}

class Foo {
	public $image				= null;
	public $args				= null;
	public $thumb				= null;
	public $from_path			= null;
	public $to_path				= null;

	public function __construct( $image, $args = array() ) {
		// Image and arguments
		$this->image			= $image;
		$this->args				= $args;

		// Add thumbnail and store thumb object
		$this->thumb 			= $this->addThumb();

		// Paths
		$this->from_path 		= kirby()->roots()->thumbs() . '/' . $this->fromFilename();
		$this->to_path 			= kirby()->roots()->thumbs() . '/' . $this->toFilename();

		if( ! file_exists( $this->to_path ) ) {
			$this->compressImage();
		}
	}

	private function fromFilename() {
		return (string)$this->thumb->filename();
	}

	private function addThumb() {
		$thumb = thumb( $this->image, $this->args );
		return $thumb;
	}

	private function toFilename() {
		return $this->str_lreplace( '.', '-min.', $this->fromFilename() );
	}

	private function str_lreplace( $search, $replace, $subject ) {
		$pos = strrpos( $subject, $search );
		if( $pos !== false ) {
			$subject = substr_replace( $subject, $replace, $pos, strlen( $search ) );
		}
		return $subject;
	}

	private function compressImage() {
		$request = curl_init();
		curl_setopt_array($request, array(
			CURLOPT_URL => "https://api.tinify.com/shrink",
			CURLOPT_USERPWD => "api:" . c::get('tinypngKey'),
			CURLOPT_POSTFIELDS => file_get_contents( $this->from_path ),
			CURLOPT_BINARYTRANSFER => true,
			CURLOPT_RETURNTRANSFER => true,
			CURLOPT_HEADER => true,
			CURLOPT_CAINFO => __DIR__ . "/cacert.pem",
			CURLOPT_SSL_VERIFYPEER => true
		));

		$response = curl_exec($request);
		if (curl_getinfo($request, CURLINFO_HTTP_CODE) === 201) {
			$headers = substr($response, 0, curl_getinfo($request, CURLINFO_HEADER_SIZE));
			foreach (explode("\r\n", $headers) as $header) {
				if (strtolower(substr($header, 0, 10)) === "location: ") {
					$request = curl_init();
					curl_setopt_array($request, array(
						CURLOPT_URL => substr($header, 10),
						CURLOPT_RETURNTRANSFER => true,
						CURLOPT_CAINFO => __DIR__ . "/cacert.pem",
						CURLOPT_SSL_VERIFYPEER => true
					));
					file_put_contents($this->to_path, curl_exec($request));
				}
			}
		} else {
			print(curl_error($request));
			print("Compression failed");
		}
	}

	public function dimensions() {
		return $this->thumb->dimensions();
	}

	public function dir() {
		return $this->thumb->dir();
	}

	public function extension() {
		return $this->thumb->extension();
	}

	public function filename() {
		return $this->toFilename();
	}

	public function height() {
		return $this->thumb->height();
	}

	public function isLandscape() {
		return $this->thumb->isLandscape();
	}

	public function isPortrait() {
		return $this->thumb->isPortrait();
	}

	public function isSquare() {
		return $this->thumb->isSquare();
	}

	public function orientation() {
		return $this->thumb->orientation();
	}

	public function ratio() {
		return $this->thumb->ratio();
	}

	public function root() {
		return $this->thumb->root();
	}

	public function type() {
		return $this->thumb->type();
	}

	public function width() {
		return $this->thumb->width();
	}

	public function original() {
		return $this->thumb;
	}

	public function __toString() {
		if( file_exists( $this->to_path ) ) {
			$filename = $this->toFilename();
		} else {
			$filename = $this->fromFilename();
		}
		return '<img src="' . kirby()->urls()->thumbs() . '/' . $filename . '" alt="">';
	}
}