import { BaseController } from "@stimulus-library/utilities";
export declare class FallbackImageController extends BaseController {
    static values: {
        placeholder: StringConstructor;
    };
    static classes: string[];
    readonly placeholderValue: string;
    readonly hasPlaceholderValue: boolean;
    addSuccessClasses: (el?: HTMLElement) => void;
    removeSuccessClasses: (el?: HTMLElement) => void;
    addFailClasses: (el?: HTMLElement) => void;
    removeFailClasses: (el?: HTMLElement) => void;
    initialize(): void;
    connect(): void;
    disconnect(): void;
    private _success;
    private _fail;
    private _hasLoadedSuccessfully;
}