I wanted to try this tool, but the upload requirements were so stringent (must be jpeg, must be same aspect ratio, must be less than 64KB) that I gave up. Would be nice if sample jpegs were provided on the page.
The tool gives me two pdfs that both hash to b8d36cccd01e5a4569ba01f9d15b54efedcd5d9f. It works... scary!
$ convert -size 512x512 canvas:red canvas_red.jpg
$ convert -size 512x512 canvas:blue canvas_blue.jpg$ convert screenshot.png -resize '500x500!' bar.jpg
or
$ sips -s format jpeg -Z 500x500 screenshot.png --out bar.jpg
Generating some workable source images is trivial. You're not interested in making a 'perfect hack pdf' for some nefarious purpose, just seeing if the service does what it says it does.
Everything is trivial if you know how to do it off the top of your head. Generating white noise samples is trivial. UV-mapping a texture to a mesh is trivial. Soldering resisters to a PCB is trivial. Generating an ARM toolchain with Yocto Project is trivial.
Is it a crime that I didn't feel like researching a bunch of CLI tools I've never heard of to try to use an app I was only mildly curious about?
For a Windows user with no decent image editor or viewer installed, though, it could certainly be a hassle.