How to properly use Yii2-imagine (thumbnail method)?

Question

Yii

Actually, the point. When using https://github.com/yiisoft/yii2-imagine the page just goes down and doesn't respond.
The code:

use yii\imagine\Image;

....

Image::thumbnail( $path , 250, 250)->save(Yii::getAlias($thumbnail_path), ['quality' => 85]);

The file is found (tried to substitute the wrong path, gives an error), but somewhere it freezes and as a result: Web page is not available
Yii debugger does not write anything, as if the page did not even try to open.