Images are controlled via the add_image_size function in your theme (Located in your functions.php file).  You can adjust this by editing the add_image_size function:

Example:

add_image_size('progression-blog', 940, 450, true);

The above will resize your image to 940 pixels by 450 pixels.  The true portion refers to the cropping.  To disable cropping, change that to false.  You can find out more on this here: https://codex.wordpress.org/Post_Thumbnails

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Image not being resized properly

If your images are being stretched or not re-sized properly, it usually means the image you uploaded is not large enough.  Make sure you are uploading images large enough.  Otherwise WordPress cannot properly crop and resize the images.

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Adjusting Image Size in Child Theme

You can also adjust image sizes by using a custom function.  This can be done by adding the code below to your functions.php file in your child theme.  Just make sure the id matches the image you want to update.

function child_theme_setup() {
    add_image_size('progression-portfolio', 600, 600, true);
}
add_action( 'after_setup_theme', 'child_theme_setup', 11 );

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Regenerate Images after changing image size

You will need to run this plugin to regenerate the images after uploading (Automatically re-sizes the images for you): https://wordpress.org/plugins/force-regenerate-thumbnails/

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WooCommerce Image Sizes

You can easily adjust the image sizes for your shop under WooCommerce > Settings > Products > Display