> ................ so if it's a type error, say it's a type error, if it's a value error say it's a value error .....?

Well, at that point I might as well just let the errors propagate up, as I am currently doing. =) The idea, I think, is to only let the errors you don't understand propagate up, while the ones you do (and expect to be relatively common, such as someone giving us a float image), you generate a custom error message for.

Hence why I want to use the second syntax @stefanv suggested, but he said it's not desired... So I want to know why.