i just updated add-product page.
For MainImage i chose 23.jpg
Data entered in MainImage = 23.jpg MainImageThumb= 23_thumb.jpg
For Image2 i chose: 24.jpg
Data entered in Image2 =24.jpg & Image2Thumb = 24_thumb.jpg25.jpg25_thumb.jpg (something wrong here )
For Image3 i chose 25.jpg
Data entered in Image3 = 1 & nothing in Image3Thumb
file attached here.