How can I, as an integrator, change the aspect ratios for image cropping in TYPO3?

Short answer

Yes — you can. In TYPO3 12/13 you can adjust crop aspect ratios per page/site/language tree via Page TSconfig (recommended when it should vary per branch) and globally via a TCA override in PHP.

Page TSconfig (recommended when it should vary per page/tree)

Enter the following under the root page (or any page where you want to override it).

# tt_content.image: override the default variant
TCEFORM.tt_content.image.config.cropVariants.default {
  allowedAspectRatios {
    # Disable free cropping
    NaN {
      title = Free
      value = 0.0
      disabled = 1
    }
    # Your custom ratios
    ratio_16_9 {
      title = 16:9
      value = 1.7777777778
    }
    ratio_4_3 {
      title = 4:3
      value = 1.3333333333
    }
    ratio_1_1 {
      title = 1:1
      value = 1.0
    }
  }
  # Optional: set a default selection
  selectedRatio = ratio_16_9
}

Multiple variants (e.g. "desktop", "mobile")

TCEFORM.tt_content.image.config.cropVariants {
  desktop {
    title = Desktop
    allowedAspectRatios {
      ratio_16_9.title = 16:9
      ratio_16_9.value = 1.7777777778
      ratio_3_2.title = 3:2
      ratio_3_2.value = 1.5
      NaN.disabled = 1
    }
    selectedRatio = ratio_16_9
  }
  mobile {
    title = Mobile
    allowedAspectRatios {
      ratio_4_5.title = 4:5
      ratio_4_5.value = 0.8
      ratio_1_1.title = 1:1
      ratio_1_1.value = 1.0
      NaN.disabled = 1
    }
    selectedRatio = ratio_4_5
  }
}

Note:

The target is always the field tt_content.image (or your FAL field). Internally this affects sys_file_reference.crop for the given relation. You disable “free” cropping via the fixed key NaN (disabled = 1).

Global via TCA override (if it should apply everywhere)

EXT:my_site/Configuration/TCA/Overrides/sys_file_reference.php (or targeted to specific tt_content fields):

$GLOBALS['TCA']['tt_content']['columns']['image']['config']['cropVariants']['default'] = [
    'title' => 'Default',
    'allowedAspectRatios' => [
        'ratio_16_9' => ['title' => '16:9', 'value' => 1.7777777778],
        'ratio_4_3'  => ['title' => '4:3',  'value' => 1.3333333333],
        'ratio_1_1'  => ['title' => '1:1',  'value' => 1.0],
        'NaN'        => ['title' => 'Free', 'value' => 0.0, 'disabled' => true],
    ],
    'selectedRatio' => 'ratio_16_9',
];

Common pitfalls

• Key names: Use your own keys like ratio_16_9 instead of just 16_9.
• NaN is the fixed key for “free” cropping.
• Address the correct target field in Page TSconfig: TCEFORM.tt_content.image.config.cropVariants... (do not use sys_file_reference in Page TSconfig).
• Clear caches after changes (system caches and reload the backend).

Benefits

• Consistent image presentation across the site or per channel (desktop/mobile)
• Better editorial guidance and faster cropping workflows
• Reduced errors by disabling undesired free-cropping if needed

Conclusion

Use Page TSconfig for per-branch flexibility and a global TCA override for system-wide defaults. This keeps your image crops consistent, controlled, and fast to manage.