I am aware that explaining to users how something could be done, if they did not figure it out themselves, is pointless and a sign of a failure of the software. I hope to get better at designing things in the future. Thanks once again for the information about the first impression of the software, it is very important to me.
No no no!
Being the incredible developer you are, my job now is to cheer you up!
I ran into the same thing with Mouser on Screenshot Captor. It's a thing where some powerful program does a lot of stuff, only to happen to miss what at least in my case was THE only use case of some smaller program. And where I am happy to have donated here, is to sometimes get a misc little feature grafted on top of that program so that all that horsepower is there for one day when I need it, but I can do my low-level hack editing on the daily basis. For me the trick to low level tools is like grabbing a blue ball point pen and a pencil and a notebook. I have done some of my best creative work with those - so then questions arise like "why can't you do precisely that on a computer?" Theoretically one day if I had my very own pet developer, you could - I'd devise a program that would *almost* mimic the kinds of tricks I use in notebooks. But until then, and grudgingly admitting that developers are people and not awesome toys, that shall wait for another day!
So let's see... if you're on a dead heat with Paint.net, except you're here and that guy is "just a random dev", then I'd like it if it is possible to graft on the few low level things I do in MS Paint, so then like S.C., your program can be my all-in-one tool. It's Not an image viewer. So far, fair enough, so that's that. Let's see what else.
1. You already have both adjust saturation and hue, so that part is down.
2. Make a customizable "favorite actions" toolbar. (I got the idea from Office 2010, see my rants on ribbons elsewhere.) If a user really only does like 4 things over and over, it becomes amazingly fast if they're all there on a little toolbar in order. For me, all I really use are the Rectangle Select, Lasso Select, Flip Horozontal, and Stretch/Shrink. So if you had a feature like right-click an option and "add to custom toolbar" that makes life a win. : )
Now, for technical points.
1. Resample doesn't seem to have an effect I understand. My goal is to stretch or shrink the picture, but doing a resample looks like it leaves it there. Also, I'd like the choice of independent horozontal and vertical relative resizing like MS Paint does.
2. Flip Horozontal would be nice - just saves a step having to rotate twice, because the 90 degree cases don't do anything for me.
3. A "Clear All Tools" bit / button would be useful. I find it rather distracting to be locked into a "select" or other tool, and I'd really rather just go back to as if I'd opened the picture the first time and do something else.
4. A "pointer" tool that doesn't do anything might be nice. The idea is that with the selects, if your hand jiggles then you've yanked a piece of your picture apart and there's a small risk of damaging the picture if you somehow can't undo it such as blundering a close-save changes. A pointer is then like a "safety" so as you're just imagining things, sorta clicking around, you can't actually hurt anything. You could combine this with the "Clear All Tools" bit.
Whew! It's a lot of words, but should be a piece of cake to do after all that other stuff is in there!