Three lines of code? Is this something you could do in three lines? I mean, only deploying this live requires way more than that. One thing people seem to forget is that building your own tools means that you also have to deploy, maintain, and fix them. If programmer time is > $100, how much will it cost you to deploy something like this? I'd rather pay the money and move onto building products that make me money.
True, but this is just a service, you're going to have to write code to integrate with it anyway, why not just call ImageMagick (or whatever) directly?
Especially if the core product can be replicated with 3 lines of code using open source libraries.