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

src/core/operations/CropImage.mjs

@@ -93,7 +93,7 @@ class CropImage extends Operation {
      */
     async run(input, args) {
         const [xPos, yPos, width, height, autocrop, autoTolerance, autoFrames, autoSymmetric, autoBorder] = args;
-        if (!isImage(new Uint8Array(input))) {
+        if (!isImage(input)) {
             throw new OperationError("Invalid file type.");
         }