         }
     }
     
-    class func delete(_ images:[PiwigoImageData],
+    static func delete(_ images:[PiwigoImageData],
                       completion: @escaping () -> Void,
                       failure: @escaping (NSError) -> Void) {
         // Create string containing pipe separated list of image ids

        return downsampledImage(from: imageSource, to: pointSize, scale: scale)
    }
    
    class func downsampledImage(from imageSource:CGImageSource, to pointSize: CGSize, scale: CGFloat) -> UIImage {
        // The default display scale for a trait collection is 0.0 (indicating unspecified).
        // We therefore adopt a scale of 1.0 when the display scale is unspecified.
        let maxDimensionInPixels = max(pointSize.width, pointSize.height) * max(scale, 1.0)

class ImageUtilities: NSObject {
    
    // MARK: - Piwigo Server Methods
    static func getInfos(forID imageId:Int, inCategoryId categoryId: Int,
                        completion: @escaping (PiwigoImageData) -> Void,
                        failure: @escaping (NSError) -> Void) {
        // Prepare parameters for retrieving image/video infos
