People have already covered most of the tools I typically use, but one I haven't seen listed yet that is sometimes convenient is python3 -m http.server which runs a small web server that shares whatever is in the directory you launched it from. I've used that to download files onto my phone before when I didn't have the right USB cables/adapters handy as well as for getting data out of VMs when I didn't want to bother setting up something more complex.
e0qdk
joined 2 years ago
On the command line, you can do this with ImageMagick (e.g. use the command
convertonce it's installed).With a (desktop) GUI, there's a bunch of programs. GIMP is probably the most well known and has a ton of capabilities but is a bit complex. I use Kolourpaint as a quick-and-dirty "MS Paint"-like program for very simple tasks where I want a GUI.
If you want a simple web UI I'm sure there is one already, but I don't know one specifically. It wouldn't be too complicated to hack something up if all you need is a quick-and-dirty file input and percentage rescale or something like that. If you don't get a better suggestion and don't know how to make something like that yourself, let me know and I can write an example.