diff --git a/src/js/utils/MergeUtils.js b/src/js/utils/MergeUtils.js
index 8f69e49e..24bd56ad 100644
--- a/src/js/utils/MergeUtils.js
+++ b/src/js/utils/MergeUtils.js
@@ -12,7 +12,7 @@
      *         - index: {Number} index where the new frames should be appended
      *         - resize: {String} either "expand" or "keep"
      *         - origin: {String} can be any of the existing AnchorWidget origins.
-     *         - addFrames: {Boolean} true if all the imported frames should be added as new frames.
+     *         - insertMode: {String} either "insert" or "add"
      *
      * @return {Piskel} The new Piskel instance created
      */
diff --git a/test/js/utils/MergeUtilsTest.js b/test/js/utils/MergeUtilsTest.js
new file mode 100644
index 00000000..d47a2c84
--- /dev/null
+++ b/test/js/utils/MergeUtilsTest.js
@@ -0,0 +1,153 @@
+describe("MergeUtils suite", function() {
+  var B = '#000000';
+  var R = '#ff0000';
+  var T = Constants.TRANSPARENT_COLOR;
+
+  var createPiskelFromGrid = function (grid, name) {
+    var frame = pskl.model.Frame.fromPixelGrid(grid);
+    var layer = pskl.model.Layer.fromFrames("l1", [frame]);
+    return pskl.model.Piskel.fromLayers([layer], 12, {
+      name: name || "piskel",
+      description: "desc"
+    });
+  };
+
+  /**
+   * Simple helper to create a monochrome sprite for the provided color,
+   * number of rows and columns.
+   */
+  var getPiskel = function (color, rows, cols) {
+    var grid = [];
+    for (var i = 0 ; i < rows ; i++) {
+      grid[i] = [];
+      for (var j = 0 ; j < cols ; j++) {
+        grid[i][j] = color;
+      }
+    }
+    return createPiskelFromGrid(grid);
+  };
+
+  it("merges 2 piskel - insertMode:add same size", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 2, 2);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "add"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(2);
+    expect(mergedPiskel.getHeight()).toBe(2);
+    expect(mergedPiskel.getLayers().length).toBe(2);
+    expect(mergedPiskel.getLayers()[0].getFrames().length).toBe(2);
+  });
+
+  it("merges 2 piskel - insertMode:insert same size", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 2, 2);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(2);
+    expect(mergedPiskel.getHeight()).toBe(2);
+    expect(mergedPiskel.getLayers().length).toBe(2);
+    expect(mergedPiskel.getLayers()[0].getFrames().length).toBe(1);
+  });
+
+  it("merges 2 piskel - resize:expand with bigger imported piskel", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 4, 4);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(4);
+    expect(mergedPiskel.getHeight()).toBe(4);
+  });
+
+  it("merges 2 piskel - resize:keep with bigger imported piskel", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 4, 4);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "keep",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(2);
+    expect(mergedPiskel.getHeight()).toBe(2);
+  });
+
+  it("merges 2 piskel - resize:expand with taller but thinner imported piskel", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 1, 4);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(2);
+    expect(mergedPiskel.getHeight()).toBe(4);
+  });
+
+  it("merges 2 piskel - resize:expand with wider but shorter imported piskel", function () {
+    var piskel1 = getPiskel(B, 2, 2);
+    var piskel2 = getPiskel(R, 4, 1);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(4);
+    expect(mergedPiskel.getHeight()).toBe(2);
+  });
+
+  it("merges 2 piskel - resize:expand with bigger original piskel", function () {
+    var piskel1 = getPiskel(B, 3, 3);
+    var piskel2 = getPiskel(R, 1, 1);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "expand",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(3);
+    expect(mergedPiskel.getHeight()).toBe(3);
+  });
+
+  it("merges 2 piskel - resize:keep with bigger original piskel", function () {
+    var piskel1 = getPiskel(B, 3, 3);
+    var piskel2 = getPiskel(R, 1, 1);
+
+    var mergedPiskel = pskl.utils.MergeUtils.merge(piskel1, piskel2, {
+      index: 0,
+      resize: "keep",
+      origin: "TOPLEFT",
+      insertMode: "insert"
+    });
+
+    expect(mergedPiskel.getWidth()).toBe(3);
+    expect(mergedPiskel.getHeight()).toBe(3);
+  });
+});