Updating with Paperclip

"_method"=>"put", "action"=>"update", "spec"=>{"photo"=>"Blue-Wild-
Flower-1-1024x768.jpg"}, "id"=>"10", "controller"=>"spec"}

If you can see the file name and not something like :
"photo"=>#<ActionController::UploadedStringIO:0xb70611f4>

There's a mistake. Maybe you forgot the multipart on the form?