attachment_fu generates wrong public_filename

Hi,

attachment_fu generates wrong public_filename.

pic.thumbnails

=> ProductPicture id: 12331, product_id: nil, parent_id: 12330,
content_type: "image/png", filename: "b_9788994035109_mid.png",
thumbnail: "mid", size: 16562, width: 205, height: 205, created_at:
"2009-10-05 02:43:50", updated_at: "2009-10-05 02:43:50",
ProductPicture id: 12332, product_id: nil, parent_id: 12330,
content_type: "image/png", filename: "b_9788994035109_thumb.png",
thumbnail: "thumb", size: 2300, width: 52, height: 52, created_at:
"2009-10-05 02:43:51", updated_at: "2009-10-05 02:43:51"

pic

ProductPicture id: 12330, product_id: 23236, parent_id: nil,
content_type: "image/gif", filename: "b_9788994035109.gif", thumbnail:
nil, size: 73990, width: 400, height: 400, created_at: "2009-10-05
02:43:50", updated_at: "2009-10-05 02:43:50"

pic.thumbnails

=> ProductPicture id: 12331, product_id: nil, parent_id: 12330,
content_type: "image/png", filename: "b_9788994035109_mid.png",
thumbnail: "mid", size: 16562, width: 205, height: 205, created_at:
"2009-10-05 02:43:50", updated_at: "2009-10-05 02:43:50", ProductPicture
id: 12332, product_id: nil, parent_id: 12330, content_type: "image/png",
filename: "b_9788994035109_thumb.png", thumbnail: "thumb", size: 2300,
width: 52, height: 52, created_at: "2009-10-05 02:43:51", updated_at:
"2009-10-05 02:43:51"

pic.public_filename

=> "/product_pictures/0001/2330/b_9788994035109.gif"

pic.public_filename(:mid)

=> "/product_pictures/0001/2330/b_9788994035109_mid.gif"

It generates ".gif" instead of ".png" when the actual type is '.png'
(gif is the parent's type)

This works ok with my dev machine but not with my production machine.

Any idea?

Thanks.

Sam