For consistency, let's pick one word for the hash used for image integrity and stick with it.  I see a mix of "checksum" and "signature."

I'd prefer "checksum" over "signature". While technically, I suppose it's really a digest, "checksum" is fine with me.  However, I don't like "signature", as I generally associated that with checks intended to verify authenticity, which is not an objective here.

http://www.library.yale.edu/iac/DPC/AN_DPC_FixityChecksFinal11.pdf