Mmh "In fact, the research phase of this project took longer than the batch processing itself.  That was clearly time well spent." I'm not so sure about this.

Mmh "In fact, the research phase of this project took longer than the batch processing itself.  That was clearly time well spent." I'm not so sure about this. A sufficiently parallelized but otherwise unresearched script could have been created in a fraction of the time. So you would just generate the correct thumbnails on new uploads and then let the batch job run for, say, two weeks. That naive approach will take you around a days worth of development time. The time you gained by doing it the naive way you then put into the rewrite of that legacy component that prevented you from on-the-fly generating the images. What you have done here is, IMHO, wasted time in a legacy solution and you wasted hardware resources for storage of the additional pictures of which probably only a minority will actually be seen anyways. Don't get me wrong: I'm sure you had a lot of fun and there's little more exciting things than seeing your code perform magnitudes quicker than the initial approach. But in the context of your quote, I have to disagree. Unless there's more background you didn't tell us about.