Late reply, but it might help googlers and I had to do something similar. The following worked:
These are the versions present on my uploader class
version :thumb do
process :resize_to_fill => [122, 70]
end
version :medium do
process :resize_to_fill => [470, 470]
end
So to get the image in a certain version I just need to do, for example:
specific_version = uploader.image.medium.read
Where medium is the version I want.
In the original question's case you need to do:
attachments.inline[@filename] = @tidbit.image.thumb.read