update mysql table with a prepend text

Hi,

I'd like to update a set of records where the column name='picture' where id>='1'.
id is the primary key, auto increment field.

The picture field has values like:
/dev/images/profile/2-6-1.png

But I'd like like to prepend the url with:
http://cosmeticguide.com/
so the picture field values should be:
http://cosmeticguide.com/dev/images/profile/2-6-1.png

How do I do this with one mysql statement?

Thank you,
vkimura