Problem with images in flash webpage

1

Hi guys, I don’t know how to solve this problem, please help. From the image attached, the black stroke around the first thumbnail is uneven and don’t show up smoothly. From the other thumbnails below, the strokes are perfectly fine. The first thumbnail was created by me in photoshop and saved as .jpg . The other 3 were premade, so I don’t know how to fix this. Thanks