{var $image='images/image.jpg'}

<img src="{$image|thumbnail: 150, 150}" />

composer.json

{
    "require":{
        "kollarovic/thumbnail": "dev-master"
    }
}

config.neon

extensions:
	thumbnail: Kollarovic\Thumbnail\DI\Extension

config.neon

thumbnail:
	thumbPathMask: 'images/thumbs/{filename}-{width}x{height}.{extension}'
	placeholder: 'http://dummyimage.com/{width}x{height}/efefef/f00&text=Image+not+found'
    

{md5} param in thumbPathMask takes file path and file name, converts it to md5 hash and then saves it in nested directories to avoid having millions of files in one folder. For example let's say md5 hash of my src location somedir/project/www/images/users/1/profile.jpg is e728fdeab7e2edda33f36fbf7a2b7c82 so using this thumbPathMask:

thumbPathMask: 'images/thumbs/{md5}/{width}x{height}-{crop}.{extension}'

it gets stored in images/thumbs/e/7/2/e728fdeab7e2edda33f36fbf7a2b7c82/{width}x{height}-{crop}.jpg