Convert as follows:

enum NS_ENUM(NSInteger, MyEnumType) {
    MyEnumTypeMicro,
    MyEnumTypeTiny,
    MyEnumTypeSmall,
    MyEnumTypeFull
};

becomes:

@objc enum ImageSizeType: Int {
    case Micro
    case Tiny
    case Small
    case Full
    case Huge
}

In Objective-C the enumerations will be available under their old names, as Swift bridges them as the enum name prefixed by the enum type name.