I wrote a small node app that watermarks images as an inside joke between friends, and I learned some pretty neat tricks along the way. The app will take a URL to an image and overlay a gigantic hand over it. On the useful scale, it is hovering at around a 3 (someone must have a use for this somewhere, right?) but it took a lot of Googling to make this work.

One of the big challenges for this was that I wanted to host it on heroku, and being a read-only filesystem I had to process all the images without touching the filesystem. Finding out how to do this in node was surprisingly difficult at the time.

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