I recall similar arguments being used when DBI's development got started. Sure, there will be big bumps to take, but I think this is worthwhile pursuit.

I would definitely investigate first which similar approaches have been done in the past: there are several packages capable of conversion between different image formats already. This API could serve as a glue for such conversions.

I think it would also be important to focus on capabilities rather than efficiency. There will always be more efficient ways to do specific conversions. The generic API is for ease of use, efficiency can be built in later if people have an itch for it.

Liz