go.talks/present: fix image size attributes The arg type for image sizes is int, using %s is wrong.
go.talks/present: fix image size attributes
The arg type for image sizes is int, using %s is wrong.

R=adg, r
CC=golang-dev
http://codereview.appspot.com/6828044

webfd/go-zh.talks,bryanxu/go-zh.talks,bryanxu/go-zh.talks,d0f/go-zh.talks,d0f/go-zh.talks,webfd/go-zh.talks,d0f/go-zh.talks,bryanxu/go-zh.talks,webfd/go-zh.talks,bryanxu/go-zh.talks,bryanxu/go-zh.talks,d0f/go-zh.talks,d0f/go-zh.talks,webfd/go-zh.talks,bryanxu/go-zh.talks,webfd/go-zh.talks,webfd/go-zh.talks,d0f/go-zh.talks