Tidied up Steganography operations. FileType and toBase64 functions now accept ArrayBuffers.

src/core/operations/InvertImage.mjs

@@ -38,7 +38,7 @@ class InvertImage extends Operation {
      * @returns {byteArray}
      */
     async run(input, args) {
-        if (!isImage(new Uint8Array(input))) {
+        if (!isImage(input)) {
             throw new OperationError("Invalid input file format.");
         }