I find that working with images in a cross-platform manner is quite tedious. Android requires 5 versions of an image (ldpi, mdpi (actual size), hdpi, xhdpi, and xxhdpi). And iOS requires 3 versions (default (actual size), @2x, and @3x)... I don't even know what versions WP takes as I haven't had the need to deal with it (yet).
So when I have a need for an image, my current process has been to build it at the largest version (xxhdpi and @3x the same), and then calculate the down-scaled sizes and scale them down.
Now, I feel as though I must be missing something simple because this can be quite time consuming since you'd need to do this for each file. Is there an easier way, or is there a need for a command line tool to do the down-scaling (note: I've already written one).
Also, other than re-sizing, are there any other steps required to make the image correct on all platforms? I've noticed that I get an iCCP warning in Android, and have to go into the droid images and pngcrush them.
Basically I'm just trying to get a handle on the whole image "thing" so that I can simplify my workflow. If there is actually a need for the command line tool that I wrote, I will open source it on Github, but I want to make sure I'm not barking up the wrong tree first. Is there already something baked in or available that I just haven't found yet?