Change image source from 'file' to 'sequence' without refreshing image data

When dealing with images throught the python API, changing an image source from 'File' to 'Sequence' should not discard the compression settings. It would be better for it to work like the image.filepath_raw which doens't refresh the image data.

It's a small request, but it would help with the image texture baking addon that I am working on. Currently after baking an image sequence and updating the texture nodes to load that sequence, the compression settings are lost and any re-renders use default settings.