Modified SwiftGen xcassets template for images. Makes static const of type UIImage or NSImage.

images-swift5.stencil

// swiftlint:disable all
// Generated using SwiftGen — https://github.com/SwiftGen/SwiftGen

{% if catalogs %}
{% set enumName %}{{param.enumName|default:"Images"}}{% endset %}
{% set enumNameForStrings %}{{param.enumNameForStrings|default:"ImageNames"}}{% endset %}
{% set imageType %}{{param.imageTypeName|default:"Image"}}{% endset %}
{% set forceNamespaces %}{{param.forceProvidesNamespaces|default:"false"}}{% endset %}
{% set accessModifier %}{% if param.publicAccess %}public{% else %}internal{% endif %}{% endset %}
#if os(macOS)
  import AppKit
#elseif os(iOS)
  import UIKit
#elseif os(iOS) || os(tvOS) || os(watchOS)
  import UIKit
#endif

// swiftlint:disable superfluous_disable_command file_length implicit_return

{% macro enumBlock assets %}
  {% call casesBlock assets "" %}
  {% if param.allValues %}

  // swiftlint:disable trailing_comma
  {% if resourceCount.image > 0 %}
    {{accessModifier}} static let allImages: [{{imageType}}] = [
      {% filter indent:2 %}{% call allValuesBlock assets "image" "" %}{% endfilter %}
    ]
  {% endif %}
  // swiftlint:enable trailing_comma
  {% endif %}
{% endmacro %}
{% macro enumStringsBlock assets %}
  {% for asset in assets %}
  {% if asset.type == "image" %}
  {{accessModifier}} static let {{asset.name|swiftIdentifier:"pretty"|lowerFirstWord|escapeReservedKeywords}} = "{{asset.value}}"
  {% elif asset.items and ( forceNamespaces == "true" or asset.isNamespaced == "true" ) %}
    {{accessModifier}} enum {{asset.name|swiftIdentifier:"pretty"|escapeReservedKeywords}} {
      {% filter indent:4 %}{% call enumStringsBlock asset.items %}{% endfilter %}
    }
  {% elif asset.items %}
  {% call enumStringsBlock asset.items %}
  {% endif %}
  {% endfor %}
{% endmacro %}
{% macro casesBlock assets assetName %}
  {% for asset in assets %}
  {% if asset.type == "image" %}
  {% set namedValue %}{% if assetName != "" %}{{imageType}}(named: {{enumNameForStrings}}{{assetName}}.{{asset.value|swiftIdentifier:"pretty"|lowerFirstWord|escapeReservedKeywords}}){% else %}{{imageType}}(named: {{enumNameForStrings}}.{{asset.value|swiftIdentifier:"pretty"|lowerFirstWord|escapeReservedKeywords}}){% endif %}{% endset %}
  {{accessModifier}} static let {{asset.name|swiftIdentifier:"pretty"|lowerFirstWord|escapeReservedKeywords}} = {{namedValue}}
  {% elif asset.items and ( forceNamespaces == "true" or asset.isNamespaced == "true" ) %}
  {{accessModifier}} enum {{asset.name|swiftIdentifier:"pretty"|escapeReservedKeywords}} {
    {% set conAssetName %}{{assetName}}.{{asset.name|swiftIdentifier:"pretty"|escapeReservedKeywords}}{% endset %}
    {% filter indent:2 %}{% call casesBlock asset.items conAssetName %}{% endfilter %}
  }
  {% elif asset.items %}
  {% call casesBlock asset.items "" %}
  {% endif %}
  {% endfor %}
{% endmacro %}
{% macro allValuesBlock assets filter prefix %}
  {% for asset in assets %}
  {% if asset.type == filter %}
  {{prefix}}{{asset.name|swiftIdentifier:"pretty"|lowerFirstWord|escapeReservedKeywords}},
  {% elif asset.items and ( forceNamespaces == "true" or asset.isNamespaced == "true" ) %}
  {% set prefix2 %}{{prefix}}{{asset.name|swiftIdentifier:"pretty"|escapeReservedKeywords}}.{% endset %}
  {% call allValuesBlock asset.items filter prefix2 %}
  {% elif asset.items %}
  {% call allValuesBlock asset.items filter prefix %}
  {% endif %}
  {% endfor %}
{% endmacro %}
// swiftlint:disable identifier_name line_length nesting type_body_length type_name

// MARK: - {{enumNameForStrings}}
{{accessModifier}} enum {{enumNameForStrings}} {
  {% if catalogs.count > 1 or param.forceFileNameEnum %}
  {% for catalog in catalogs %}
  {{accessModifier}} enum {{catalog.name|swiftIdentifier:"pretty"|escapeReservedKeywords}} {
    {% filter indent:2 %}{% call enumStringsBlock catalog.assets %}{% endfilter %}
  }
  {% endfor %}
  {% else %}
  {% call enumStringsBlock catalogs.first.assets %}
  {% endif %}
}

// MARK: - Image Assets
{{accessModifier}} enum {{enumName}} {
  {% if catalogs.count > 1 or param.forceFileNameEnum %}
  {% for catalog in catalogs %}
  {{accessModifier}} enum {{catalog.name|swiftIdentifier:"pretty"|escapeReservedKeywords}} {
    {% filter indent:2 %}{% call enumBlock catalog.assets %}{% endfilter %}
  }
  {% endfor %}
  {% else %}
  {% call enumBlock catalogs.first.assets %}
  {% endif %}
}
// swiftlint:enable identifier_name line_length nesting type_body_length type_name

// MARK: - Implementation Details
{% if resourceCount.image > 0 %}

#if os(macOS)
{{accessModifier}} typealias Image = NSImage
#elseif os(iOS) || os(tvOS) || os(watchOS)
{{accessModifier}} typealias Image = UIImage
#endif

{{accessModifier}} extension {{imageType}} {
  convenience fileprivate init(named: String) {
    #if os(iOS) || os(tvOS)
    let bundle = {{param.bundle|default:"BundleToken.bundle"}}
    self.init(named: named, in: bundle, compatibleWith: nil)!
    #elseif os(macOS)
    self.init(named: NSImage.Name(named))!
    #elseif os(watchOS)
    self.init(named: named)!
    #endif
  }
}
{% endif %}

{% if not param.bundle %}

// swiftlint:disable convenience_type
private final class BundleToken {
  static let bundle: Bundle = {
    Bundle(for: BundleToken.self)
  }()
}
// swiftlint:enable convenience_type
{% endif %}
{% else %}
// No assets found
{% endif %}

You don't have to call .image every time now.
Output:

internal enum ImageNames {
  internal static let calendar = "CalendarIcon"
}
internal enum Images {
  internal static let calendar = Image(named: ImageNames.calendar)
}