Each image in the slide has different size. For both Concentric and Warp transitions, the image's position is shifted before the animation start (usually about 50~100 pixels toward the top left but it varies)
Also, on Firefox (v23.0), Tiles3D and Blinds3D cause the image to scale up, becoming 2px wider and 2px higher (1px toward all 4 sides) before animation start.
The bug did not occur on webkit browsers.
I forced the the slider's size to 800x600 during initialization:
window.myFlux = new flux.slider('#slider', { autoplay: false, captions: true, controls: true, width: 800, height: 600 });
Each image in the slide has different size. For both Concentric and Warp transitions, the image's position is shifted before the animation start (usually about 50~100 pixels toward the top left but it varies)