Magento 2 Image Resize Issue

Either set keepFrame to true, so it's always exact 160x210, or set keepAspectRatio to false.

Now it is making sure both width and height won't exceed the values you feed it. But since you don't want a frame, and want to keep your aspect ratio, it has to change both width and height in the same ratio.

<?php 
echo $this->helper('catalog/image')->init($_product, 'small_image')
    ->constrainOnly(false)
    ->keepAspectRatio(true)
    ->keepFrame(true)
    ->resize(160, 210);
?>

Edit: For cropping you need to use Varien_Image. Unfortunately the Mage_Catalog_Helper_Image doesn't offer a method to return the Varien_Image class. So you need to make a custom module to make it possible to crop.

See https://stackoverflow.com/questions/9492770/magento-crop-image for an example.

Basically it says you need to make your own helper and extend Mage_Catalog_Helper_Image, so you can use $this->_getModel()->getImageProcessor()->crop()

1) you can define any new image type in the view.xml. To use it you have to pass the image id to the image helper used like here for example: https://github.com/magento/magento2/blob/develop/app/code/Magento/Catalog/Block/Product/View/Gallery.php#L60

2) if I got the right widget here, you have to override a differrent image id:

grid: https://github.com/magento/magento2/blob/develop/app/code/Magento/Catalog/view/frontend/templates/product/widget/new/content/new_grid.phtml#L21

list: https://github.com/magento/magento2/blob/develop/app/code/Magento/Catalog/view/frontend/templates/product/widget/new/content/new_list.phtml#L21

So you would have to override these images in your view.xml:

grid: https://github.com/magento/magento2/blob/develop/app/design/frontend/Magento/blank/etc/view.xml#L55

list: https://github.com/magento/magento2/blob/develop/app/design/frontend/Magento/blank/etc/view.xml#L59